What do you think?
Rate this book
Ruby and Cordelia Mysteries #3
The Key to a Killer
Not yet published
Expected 20 Oct 26A woman and her ghost roommate investigate their most personal case yet in Olivia Blacke’s The Key to a Killer, the next book in the Anthony Award winning Ruby and Cordelia Mysteries.
When Ruby Young discovered that her Boston apartment was haunted, she did what any reasonable person would do: befriend the ghost. Their relationship overcame a shaky start—Cordelia Graves never wanted a roommate in life, she certainly didn’t want one in death. After working together to solve a few murders, the two are close friends, but there’s a lingering question neither of them have been able to answer: what led to Cordelia’s death?
Lately things have been adding up that suggest foul play. And when Cordelia’s memories of that day start to come back, the roommates can’t ignore it anymore: Cordelia was murdered. Ruby and Cordelia are going to have to piece together what Cordelia’s final days looked like—otherwise a killer could go free.
When Ruby Young discovered that her Boston apartment was haunted, she did what any reasonable person would do: befriend the ghost. Their relationship overcame a shaky start—Cordelia Graves never wanted a roommate in life, she certainly didn’t want one in death. After working together to solve a few murders, the two are close friends, but there’s a lingering question neither of them have been able to answer: what led to Cordelia’s death?
Lately things have been adding up that suggest foul play. And when Cordelia’s memories of that day start to come back, the roommates can’t ignore it anymore: Cordelia was murdered. Ruby and Cordelia are going to have to piece together what Cordelia’s final days looked like—otherwise a killer could go free.
368 pages, Hardcover
Expected publication October 20, 2026
About the author
Olivia Blacke
12 books697 followersMysterious, Spooky, Cozy & Kooky
Olivia Blacke (she/her) is the Anthony Award-winning author of the paranormal Ruby and Cordelia Mysteries, as well as the cozy Record Shop Mysteries and the Brooklyn Murder Mysteries. She had her first ghost encounter when she was only five years old, but wasn’t involved with an active crime scene until much later, when she accidentally stepped into a chalk outline on a Manhattan sidewalk. She uses her otherwise useless criminology degree to inspire darkly humorous paranormal mysteries. Olivia wants to be a unicorn when she grows up.
Social media links, blog, and up-to-date news is found at: OliviaBlacke.com
Newsletter signup: http://www.oliviablacke.com/newsletter
Olivia Blacke (she/her) is the Anthony Award-winning author of the paranormal Ruby and Cordelia Mysteries, as well as the cozy Record Shop Mysteries and the Brooklyn Murder Mysteries. She had her first ghost encounter when she was only five years old, but wasn’t involved with an active crime scene until much later, when she accidentally stepped into a chalk outline on a Manhattan sidewalk. She uses her otherwise useless criminology degree to inspire darkly humorous paranormal mysteries. Olivia wants to be a unicorn when she grows up.
Social media links, blog, and up-to-date news is found at: OliviaBlacke.com
Newsletter signup: http://www.oliviablacke.com/newsletter
Ratings & Reviews
Friends & Following
Create a free account to discover what your friends think of this book!
Community Reviews
Displaying 1 - 30 of 139 reviews
Review of advance copy received from Netgalley
This is the third installment in the Ruby and Cordelia mysteries, and we finally get to dive into the mystery surrounding Cordy’s murder! There are plenty of questions, lots of suspects, and, of course, all the entertaining capers these two get themselves into. We also get to learn a little more about Cordelia’s brother, which adds another interesting layer to the story.
I definitely recommend reading this series in order, as there’s quite a bit of backstory you’d miss if you jumped in with this book as a standalone. If you enjoy fun, quirky, ghostly mysteries filled with intrigue and a bit of mischief, this series is one you won’t want to miss!
Thank you to Net Galley and St Martin's Press for allowing me to read this ARC in exchange for my honest review.
I definitely recommend reading this series in order, as there’s quite a bit of backstory you’d miss if you jumped in with this book as a standalone. If you enjoy fun, quirky, ghostly mysteries filled with intrigue and a bit of mischief, this series is one you won’t want to miss!
Thank you to Net Galley and St Martin's Press for allowing me to read this ARC in exchange for my honest review.
Review of advance copy received from NetGalley
Olivia Blacke's "The Key to a Killer: A Ruby and Cordelia Mystery" is a humorous paranormal cozy mystery novel. It follows the upbeat Ruby and the ghost Cordelia as they solve a murder mystery. I especially enjoyed the bonding between these two unlikely characters, the 1980s lingo of the ghost Harp, and its message of believing in oneself. This is the third entry in the Ruby and Cordelia Mysteries, and is best enjoyed when read in order due to an ongoing plot thread. I look forward to joining Ruby and Cordelia as they solve their next case. I am grateful to St. Martin's Press/Minotaur Books, Olivia Blacke, and NetGalley for the opportunity to read an advanced reader copy of this delightful novel. This is my honest opinion.
Review of advance copy received from NetGalley
I came into The Key to a Killer having never met Ruby or Cordelia before, which means I had to adjust very quickly to the fact that Ruby is alive, Cordelia is dead, they share an apartment, and they have apparently reached the stage of friendship where one person handles spiders and the other casually suggests, “Hey, maybe we should solve your murder.” Cordelia has spent months refusing to go into the bathroom because that is where her body was found, but Ruby needs help, so in she goes. Honestly, if your ghost roommate will confront her own death room because you cannot deal with a spider, that friendship has moved beyond leases and security deposits.
Ruby is basically still learning how to be a functioning adult while Cordelia is hovering nearby with the exhausted protectiveness of someone who has already made most of the bad decisions Ruby is currently considering. Their communication system is hilariously inconvenient because, minor issue, one of them no longer has a body. They use magnets, objects, gestures, whatever works, and somehow these two still communicate better than half the married couples I know. Cordelia can also physically interact with things enough to acquire clothes and snacks for Ruby, which raises several legal questions I chose not to pursue because free ghost delivery is an amenity landlords should absolutely be advertising.
Then Cordelia starts remembering pieces of the day she died, and suddenly everybody from her old life looks suspicious as hell. Her married former boss, whom she was sleeping with. His wife. Other coworkers. A rival tech company. Someone seen leaving with a computer case. Corporate secrets that may or may not have been stolen. Cordelia apparently lived the kind of life where creating a suspect list requires extra refrigerator space. Meanwhile Ruby now works at the same company Cordelia did, because apparently moving into a dead woman’s apartment and inheriting her ghost was not enough entanglement for one person.
And THEN Ian shows up. Cordelia’s brother is fresh out of prison, has been breaking into the apartment looking for clues from his dead sister, and eventually learns that Cordelia is still there. This could have become unbelievably weird, but instead it punched me directly in the feelings. Ian and Cordelia clearly have history, pain, and love tangled together in that very specific sibling way where you can be furious with somebody and still want to crawl through a wall to protect them. Cordelia being able to reconnect with him while Ruby basically translates between the living and dead was much sweeter than I expected from a book where everyone is also trying to identify a murderer.
Ruby, meanwhile, has other problems because apparently solving your ghost roommate’s homicide does not excuse you from workplace drama, apartment break-ins, suspicious neighbors, or romantic complications. Tosh, the guy across the hall, works for the rival tech company. Penny, a reporter, is sniffing around the burglaries. Ian is Ian. Ruby keeps collecting complicated people like she has a punch card. And because I hadn’t read the first two Ruby and Cordelia mysteries, I occasionally felt like I had wandered into a friend group that already had several inside jokes, but I could still follow what everyone was doing and, more importantly, why Cordelia mattered so much to Ruby.
What really got me was that Ruby does not treat solving Cordelia’s murder like a fun little mystery project. This is her friend. Cordelia is right there beside her, remembering pieces of her own death and realizing that people she trusted might have been involved. There is something quietly brutal about investigating your own final day when you cannot change any of it. Even if Ruby finds the answer, Cordelia is still dead. That truth just sits there underneath all their banter, and the book wisely lets it hurt without making a speech about it.
The actual investigation kept sending me toward one suspicious person after another because Cordelia’s former life was MESSY. Every time I thought, obviously this person had a reason, another person wandered in carrying an affair, corporate espionage, jealousy, burglary, or some deeply questionable behavior. At one point I realized Ruby and Cordelia’s suspect list was starting to feel less like detective work and more like Cordelia conducting the world’s bleakest exit interview. The reveal itself did not hit quite as explosively as all those possibilities had me expecting, but I genuinely did not guess where it was going, and the answer made Cordelia’s death feel sad in a completely different way.
Mostly, though, I finished wanting more of these two. Cordelia is prickly and protective. Ruby is kind and occasionally so trusting that I wanted Cordelia to physically drag her away from several situations, which, being a ghost, she might eventually figure out how to do. Watching their friendship work despite the small logistical inconvenience of death was easily my favorite part. Now I’m the idiot who started with book three and has to go backward because apparently I need to know exactly how these women went from unwilling paranormal roommates to solving murders together like this is a perfectly reasonable household hobby.
The Key to a Killer gets 4 stars from me. I came in with zero history with Ruby and Cordelia and left emotionally invested in a dead woman, worried about her brother, suspicious of half a Boston tech company, and convinced that refrigerator magnets are wildly underutilized in paranormal communication. This was cozy, funny, surprisingly tender, and just messy enough that I am absolutely going back for the earlier books.
Whodunity Award: For Making “My Roommate Was Murdered” Somehow Less Complicated Than “My Roommate Is a Ghost and We Share a Refrigerator”
Thank you to St. Martin’s Press and NetGalley for the ARC, and for introducing me to a rental situation where the apartment comes furnished, the previous tenant never technically moved out, and solving her murder appears to be included in the lease.
Ruby is basically still learning how to be a functioning adult while Cordelia is hovering nearby with the exhausted protectiveness of someone who has already made most of the bad decisions Ruby is currently considering. Their communication system is hilariously inconvenient because, minor issue, one of them no longer has a body. They use magnets, objects, gestures, whatever works, and somehow these two still communicate better than half the married couples I know. Cordelia can also physically interact with things enough to acquire clothes and snacks for Ruby, which raises several legal questions I chose not to pursue because free ghost delivery is an amenity landlords should absolutely be advertising.
Then Cordelia starts remembering pieces of the day she died, and suddenly everybody from her old life looks suspicious as hell. Her married former boss, whom she was sleeping with. His wife. Other coworkers. A rival tech company. Someone seen leaving with a computer case. Corporate secrets that may or may not have been stolen. Cordelia apparently lived the kind of life where creating a suspect list requires extra refrigerator space. Meanwhile Ruby now works at the same company Cordelia did, because apparently moving into a dead woman’s apartment and inheriting her ghost was not enough entanglement for one person.
And THEN Ian shows up. Cordelia’s brother is fresh out of prison, has been breaking into the apartment looking for clues from his dead sister, and eventually learns that Cordelia is still there. This could have become unbelievably weird, but instead it punched me directly in the feelings. Ian and Cordelia clearly have history, pain, and love tangled together in that very specific sibling way where you can be furious with somebody and still want to crawl through a wall to protect them. Cordelia being able to reconnect with him while Ruby basically translates between the living and dead was much sweeter than I expected from a book where everyone is also trying to identify a murderer.
Ruby, meanwhile, has other problems because apparently solving your ghost roommate’s homicide does not excuse you from workplace drama, apartment break-ins, suspicious neighbors, or romantic complications. Tosh, the guy across the hall, works for the rival tech company. Penny, a reporter, is sniffing around the burglaries. Ian is Ian. Ruby keeps collecting complicated people like she has a punch card. And because I hadn’t read the first two Ruby and Cordelia mysteries, I occasionally felt like I had wandered into a friend group that already had several inside jokes, but I could still follow what everyone was doing and, more importantly, why Cordelia mattered so much to Ruby.
What really got me was that Ruby does not treat solving Cordelia’s murder like a fun little mystery project. This is her friend. Cordelia is right there beside her, remembering pieces of her own death and realizing that people she trusted might have been involved. There is something quietly brutal about investigating your own final day when you cannot change any of it. Even if Ruby finds the answer, Cordelia is still dead. That truth just sits there underneath all their banter, and the book wisely lets it hurt without making a speech about it.
The actual investigation kept sending me toward one suspicious person after another because Cordelia’s former life was MESSY. Every time I thought, obviously this person had a reason, another person wandered in carrying an affair, corporate espionage, jealousy, burglary, or some deeply questionable behavior. At one point I realized Ruby and Cordelia’s suspect list was starting to feel less like detective work and more like Cordelia conducting the world’s bleakest exit interview. The reveal itself did not hit quite as explosively as all those possibilities had me expecting, but I genuinely did not guess where it was going, and the answer made Cordelia’s death feel sad in a completely different way.
Mostly, though, I finished wanting more of these two. Cordelia is prickly and protective. Ruby is kind and occasionally so trusting that I wanted Cordelia to physically drag her away from several situations, which, being a ghost, she might eventually figure out how to do. Watching their friendship work despite the small logistical inconvenience of death was easily my favorite part. Now I’m the idiot who started with book three and has to go backward because apparently I need to know exactly how these women went from unwilling paranormal roommates to solving murders together like this is a perfectly reasonable household hobby.
The Key to a Killer gets 4 stars from me. I came in with zero history with Ruby and Cordelia and left emotionally invested in a dead woman, worried about her brother, suspicious of half a Boston tech company, and convinced that refrigerator magnets are wildly underutilized in paranormal communication. This was cozy, funny, surprisingly tender, and just messy enough that I am absolutely going back for the earlier books.
Whodunity Award: For Making “My Roommate Was Murdered” Somehow Less Complicated Than “My Roommate Is a Ghost and We Share a Refrigerator”
Thank you to St. Martin’s Press and NetGalley for the ARC, and for introducing me to a rental situation where the apartment comes furnished, the previous tenant never technically moved out, and solving her murder appears to be included in the lease.
Review of advance copy received from NetGalley
ARC by NetGalley📱📖 Read on Kindle
📃 368 pages | ⏱ Duration: 4 hours
Genre: Paranormal Cozy Mystery
🏷️ Publisher name: Minotaur Books
📅 Publication date: October 20, 2026
Ruby and Cordy are simply a joy to spend time with. By this third book, Ruby has grown into herself. She is less shy and far more willing to be blunt with Cordy, and that growth gives the friendship more depth and the banter more bite. I enjoyed the dynamic more than ever.
This installment is also the most personal for the series, as the central mystery of how Cordelia died takes center stage. It brings to a close the arcs that have run through the previous two books: the question of Cordy's death and the leaked secrets at TrendCelerate. Long-time readers will appreciate the payoff.
Ian remains as frustrating here as in the earlier books, but his love for his sister shines through. Given everything Cordy does for him in this installment (no spoilers!), I'm hoping he finally becomes the reliable brother she deserves.
Blacke has a real talent for world-building. Her characters feel so believable that you root for them as if they were people you know. My one reservation is how the TrendCelerate leak was resolved. After two books of build-up, the resolution felt underwhelming, and I had hoped for a stronger payoff. It was the only thing that didn't fully work for me.
With the main mysteries now solved, I hope the series continues. I'm not ready to say goodbye to Ruby and Cordy, and I'll admit, somewhat grudgingly, that I'm curious what Ian will get up to next.
Would I recommend it?
If you have followed Ruby and Cordy from the beginning, The Key to a Killer is the one you have been waiting for. The mystery of how Cordelia died finally takes center stage, and the friendship between the two has more bite than ever. The TrendCelerate resolution felt underwhelming after two books of build-up, but I still had a great time. This is a series I am not ready to leave. It publishes on October 20, 2026, so add it to your TBR and mark the date in your calendar.
📃 368 pages | ⏱ Duration: 4 hours
Genre: Paranormal Cozy Mystery
🏷️ Publisher name: Minotaur Books
📅 Publication date: October 20, 2026
Ruby and Cordy are simply a joy to spend time with. By this third book, Ruby has grown into herself. She is less shy and far more willing to be blunt with Cordy, and that growth gives the friendship more depth and the banter more bite. I enjoyed the dynamic more than ever.
This installment is also the most personal for the series, as the central mystery of how Cordelia died takes center stage. It brings to a close the arcs that have run through the previous two books: the question of Cordy's death and the leaked secrets at TrendCelerate. Long-time readers will appreciate the payoff.
Ian remains as frustrating here as in the earlier books, but his love for his sister shines through. Given everything Cordy does for him in this installment (no spoilers!), I'm hoping he finally becomes the reliable brother she deserves.
Blacke has a real talent for world-building. Her characters feel so believable that you root for them as if they were people you know. My one reservation is how the TrendCelerate leak was resolved. After two books of build-up, the resolution felt underwhelming, and I had hoped for a stronger payoff. It was the only thing that didn't fully work for me.
With the main mysteries now solved, I hope the series continues. I'm not ready to say goodbye to Ruby and Cordy, and I'll admit, somewhat grudgingly, that I'm curious what Ian will get up to next.
Would I recommend it?
If you have followed Ruby and Cordy from the beginning, The Key to a Killer is the one you have been waiting for. The mystery of how Cordelia died finally takes center stage, and the friendship between the two has more bite than ever. The TrendCelerate resolution felt underwhelming after two books of build-up, but I still had a great time. This is a series I am not ready to leave. It publishes on October 20, 2026, so add it to your TBR and mark the date in your calendar.
Review of advance copy received from NetGalley
Special thanks to NetGalley and the publisher for a free, electronic ARC of this novel received in exchange for an honest review.
Expected pub date: Oct. 20, 2026
Genre: Mystery, Paranormal
Synopsis:When Ruby Young discovered that her Boston apartment was haunted, she did what any reasonable person would do: befriend the ghost. After working together to solve a few murders, the two are now close friends, but there’s a lingering question neither of them have been able to answer: what led to Cordelia’s death? Lately things have been adding up that suggest foul play. And when Cordelia’s memories of that day start to come back, the roommates can’t ignore it anymore: Cordelia was murdered. Ruby and Cordelia are going to have to piece together what Cordelia’s final days looked like—otherwise a killer could go free.
Overall: This is the third novel in the Ruby and Cordelia series of novels and this is one where the previous novels should be read before taking this one on. The previous stories provide a lot of important background and character development that, if missed, will leave the reader with questions, so I suggest this series be read in chronological order. "Key" is a dual protagonist, narrated by both Ruby and Cordelia in turn, as they try to solve the mystery of Cordelia's death. The ending itself was anticlimactic, but it provided much-needed closure to the question that has been haunting fans from the beginning- what happened to Cordelia? I have no doubt that the unlikely friends will be back to solve another mystery and I look forward to it.
Expected pub date: Oct. 20, 2026
Genre: Mystery, Paranormal
Synopsis:When Ruby Young discovered that her Boston apartment was haunted, she did what any reasonable person would do: befriend the ghost. After working together to solve a few murders, the two are now close friends, but there’s a lingering question neither of them have been able to answer: what led to Cordelia’s death? Lately things have been adding up that suggest foul play. And when Cordelia’s memories of that day start to come back, the roommates can’t ignore it anymore: Cordelia was murdered. Ruby and Cordelia are going to have to piece together what Cordelia’s final days looked like—otherwise a killer could go free.
Overall: This is the third novel in the Ruby and Cordelia series of novels and this is one where the previous novels should be read before taking this one on. The previous stories provide a lot of important background and character development that, if missed, will leave the reader with questions, so I suggest this series be read in chronological order. "Key" is a dual protagonist, narrated by both Ruby and Cordelia in turn, as they try to solve the mystery of Cordelia's death. The ending itself was anticlimactic, but it provided much-needed closure to the question that has been haunting fans from the beginning- what happened to Cordelia? I have no doubt that the unlikely friends will be back to solve another mystery and I look forward to it.
Review of advance copy received from Publisher
Ruby and Cordelia are an unlikely crime solving duo. Not only is Cordelia about twenty years older but she is also a ghost! That doesn't stop them from becoming best friends though. They've already solved two murders together and now it's finally time to figure out what really happened the night Cordelia died. Not only do they have the usual communication issues but Cordelia's memory issues as well.
This mystery series is different in such an interesting way. You've got a ghost or two. It's not scary but not quite cozy either. There is humor but also sadness. I love watching Ruby and Cordelia grow as characters. I love the introduction of Cordelia's brother, Ian. The supporting characters are a unique mix. Everyone is flawed and some can't quite be figured out. They're not all bad, or are they? It makes for plenty of suspects.
This series is just as much about the characters as it is the mystery. I really enjoy the author's writing style. I didn't guess the killer but I felt I should have. I'm happy with who it turned out to be though. Some interesting things happen that will be nice to see what comes of them in the next book.
Thank you to Minotaur Books for the eARC! All opinions are my own.
This mystery series is different in such an interesting way. You've got a ghost or two. It's not scary but not quite cozy either. There is humor but also sadness. I love watching Ruby and Cordelia grow as characters. I love the introduction of Cordelia's brother, Ian. The supporting characters are a unique mix. Everyone is flawed and some can't quite be figured out. They're not all bad, or are they? It makes for plenty of suspects.
This series is just as much about the characters as it is the mystery. I really enjoy the author's writing style. I didn't guess the killer but I felt I should have. I'm happy with who it turned out to be though. Some interesting things happen that will be nice to see what comes of them in the next book.
Thank you to Minotaur Books for the eARC! All opinions are my own.
Review of advance copy received from NetGalley
It's the odd couple relationship still being forged between Ruby Young and the still new to her ghostly existence Cordelia Graves that draws me to this series as much as, maybe more than the mystery itself. Don't get me wrong. There's nothing wrong with the mysteries. They're fine being a character driven reader, I find the contrast between the two main characters particularly intriguing as we watch the learning cure for a ghost with all its possibilities and "can't do" actions so unique and seemingly ever changing. That's in comparison to other works that feature ghosts with far more latitude and abilities. Here, Cordelia's tendency to blow up modern technology, too, helps keep the focus on good ol' brain power and the non-computerized aspects of finding clues and evidence. While certainly not entirely ignored, that element adds another layer of interest.
Personal connections and relationships aren't cut and dried, either. The chapters alternate between the two main characters, so we get to spend quite a bit of time with each, frequently seeing their different reactions to the same events. Ruby seems to have adapted fairly well to having a ghost as a roommate while Cordelia is still often seen flailing about trying to make sense of what really happened to her and what all this being a ghost is about. I mean, how you you react finding yourself as a ghost and having no memory of what or who killed you? Despite the still rudimentary, awkward communications between Ruby and Cordelia, Ruby finally makes it clear that she thinks it is time they focus on trying to sort it all out. And, yes, you'll gradually come to learn more of the story and events leading to Cordelia's death. In the process, we get to know more about reporter Penny, a sorta friend to Ruby, and the one who found Cordelia's body, an act that there is far more to than was known. You'll also get to spend more time with Ian, Cordelia's brother. Gotta admit, his lock picking skills may come in handy.
Bottom line, while I won't detail the plot and I'm still not quite sure that as fascinated as I find the situation that I even like the living and dead duo, I find the whole scenario intriguing. Two more unlikely friends I cannot imagine. I was honestly expecting more of an explosive finale as we learn who Cordelia's killer was but, when I thought about it, it was all somehow fitting. One sweet moment comes when Ruby gets a glimpse at an old photo of Cordelia and Ian as children, the first true image she's had of her ghostly friend. And what do all the burglaries have to do with anything? Let's face it, Boston's best face isn't visible much in this series. There's even a tying up of the goings on at Cordelia's old job, now Ruby's, so lots of ground is covered. Thanks #StMartin'sPress - #MinotaurBooks for introducing me to this unusual but intriguing odd pair and allowing me an early look at this, oh, so personal glimpse into the ongoing, ever changing relationship between Ruby and Cordelia.
Personal connections and relationships aren't cut and dried, either. The chapters alternate between the two main characters, so we get to spend quite a bit of time with each, frequently seeing their different reactions to the same events. Ruby seems to have adapted fairly well to having a ghost as a roommate while Cordelia is still often seen flailing about trying to make sense of what really happened to her and what all this being a ghost is about. I mean, how you you react finding yourself as a ghost and having no memory of what or who killed you? Despite the still rudimentary, awkward communications between Ruby and Cordelia, Ruby finally makes it clear that she thinks it is time they focus on trying to sort it all out. And, yes, you'll gradually come to learn more of the story and events leading to Cordelia's death. In the process, we get to know more about reporter Penny, a sorta friend to Ruby, and the one who found Cordelia's body, an act that there is far more to than was known. You'll also get to spend more time with Ian, Cordelia's brother. Gotta admit, his lock picking skills may come in handy.
Bottom line, while I won't detail the plot and I'm still not quite sure that as fascinated as I find the situation that I even like the living and dead duo, I find the whole scenario intriguing. Two more unlikely friends I cannot imagine. I was honestly expecting more of an explosive finale as we learn who Cordelia's killer was but, when I thought about it, it was all somehow fitting. One sweet moment comes when Ruby gets a glimpse at an old photo of Cordelia and Ian as children, the first true image she's had of her ghostly friend. And what do all the burglaries have to do with anything? Let's face it, Boston's best face isn't visible much in this series. There's even a tying up of the goings on at Cordelia's old job, now Ruby's, so lots of ground is covered. Thanks #StMartin'sPress - #MinotaurBooks for introducing me to this unusual but intriguing odd pair and allowing me an early look at this, oh, so personal glimpse into the ongoing, ever changing relationship between Ruby and Cordelia.
Review of advance copy received from NetGalley
This is a good addition to this series. It kinda wraps everything up into a neat little bow. It makes me wonder if this is the last book in this series? It was a surprise as to who the murderer was.
Want to Read
March 15, 2026I can’t wait for this book!! I loved the first two!
Review of advance copy received from NetGalley
3.75 stars. This is the third in the cozy mystery series, The Ruby and Cordelia Mysteries, and my first read in it and by this author. The series has won the Anthony Award, considered a literary award for mystery and crime books.
Some background: Ruby and Cordelia are an unlikely duo. When Ruby Young moves into her Boston apartment she finds out it’s haunted. Cordelia Graves isn’t an easy friend to make but over two books in which they solve murders, they are now the best of friends in #3.
This book is about solving Cordelia’s murder. Ruby takes a job at Cordelia’s old employer, TrendCelebrate, setting her up to be with the people Cordelia was with before her murder. There is a long list of suspects who are “possibles” including a mysterious man who took Cordelia’s computer leading to an accusation they Cordelia may have sold company secrets. What about her affair with her married boss - she wasn’t the only one. Then there are the break-ins in the apartment building. Lots of ideas but whodunnit?
We do learn who killed Cordelia - it’s a rather anti-climatic ending it seemed to me. Cordelia and Ruby are a cute pair - I liked the scene where Ruby found Cordelia’s driver’s license and seeing a picture of her further first time. I could tell these two were great friends. While I enjoyed the book I think it would have been a more enjoyable read if I had read the first two. What one often misses in picking up a book into a series is the character development that really is the glue in forming an attachment to a series. I think I’d definitely want to start over and get into this series as it’s such a perfect cozy one.
This is a fine cozy mystery. Best for those who have read the first two book in the series.
My thanks to NetGalley and Minotaur for granting me access to this ARC.
Some background: Ruby and Cordelia are an unlikely duo. When Ruby Young moves into her Boston apartment she finds out it’s haunted. Cordelia Graves isn’t an easy friend to make but over two books in which they solve murders, they are now the best of friends in #3.
This book is about solving Cordelia’s murder. Ruby takes a job at Cordelia’s old employer, TrendCelebrate, setting her up to be with the people Cordelia was with before her murder. There is a long list of suspects who are “possibles” including a mysterious man who took Cordelia’s computer leading to an accusation they Cordelia may have sold company secrets. What about her affair with her married boss - she wasn’t the only one. Then there are the break-ins in the apartment building. Lots of ideas but whodunnit?
We do learn who killed Cordelia - it’s a rather anti-climatic ending it seemed to me. Cordelia and Ruby are a cute pair - I liked the scene where Ruby found Cordelia’s driver’s license and seeing a picture of her further first time. I could tell these two were great friends. While I enjoyed the book I think it would have been a more enjoyable read if I had read the first two. What one often misses in picking up a book into a series is the character development that really is the glue in forming an attachment to a series. I think I’d definitely want to start over and get into this series as it’s such a perfect cozy one.
This is a fine cozy mystery. Best for those who have read the first two book in the series.
My thanks to NetGalley and Minotaur for granting me access to this ARC.
Review of advance copy received from NetGalley
In this third Ruby and Cordelia mystery the roommates and partners in detection are finally ready to solve the mystery of Cordelia's murder. The problem is that Cordelia doesn't remember her death or the day leading up to it.
Ruby, who works for the same company Cordelia worked for before her death, wonders if Cordelia's death stems from her long-time affair with her married boss or if it has something to do with some software the company claims was stolen by a rival company.
Cordelia is sure that her lover didn't kill her, but her surety is based on feelings and not evidence. But her lover isn't the only possible suspect. A strange man was seen leaving Cordelia's apartment on the day she died carrying a laptop case. Cordelia's laptop along with her wallet, phone, keys, and watch all were missing when her body was found.
Then there is the reporter who discovered her body and who believed that Cordelia was going to blow the whistle on her company. That same reporter is working on an article about the statistically large number of burglaries in the apartment building.
Both Ruby and Cordelia are investigating what happened when Cordelia died in their own way. Ruby has been befriended by a man who works for the rival software company, and she hopes to get some answers from him. Cordelia is also lurking around the company and blowing up anything electronic that she gets close to.
This was an engaging mystery about two very unlikely friends and even less likely detectives.
Ruby, who works for the same company Cordelia worked for before her death, wonders if Cordelia's death stems from her long-time affair with her married boss or if it has something to do with some software the company claims was stolen by a rival company.
Cordelia is sure that her lover didn't kill her, but her surety is based on feelings and not evidence. But her lover isn't the only possible suspect. A strange man was seen leaving Cordelia's apartment on the day she died carrying a laptop case. Cordelia's laptop along with her wallet, phone, keys, and watch all were missing when her body was found.
Then there is the reporter who discovered her body and who believed that Cordelia was going to blow the whistle on her company. That same reporter is working on an article about the statistically large number of burglaries in the apartment building.
Both Ruby and Cordelia are investigating what happened when Cordelia died in their own way. Ruby has been befriended by a man who works for the rival software company, and she hopes to get some answers from him. Cordelia is also lurking around the company and blowing up anything electronic that she gets close to.
This was an engaging mystery about two very unlikely friends and even less likely detectives.
October 11, 2026
The Key to a Killer 4⭐️
(A Ruby and Cordelia Mystery: Book 3)
My favorite non-spooky ghost series is back! Cordelia (a ghost) and Ruby (the tenant who took over her apartment) continue to team up as an unusual duo to solve mysteries. Now is the time to solve Cordelia’s own murder. Cordelia can walk through walls, teleport, and blow up electronics, but she can’t remember the hours/days leading up to her death. With Ruby’s help, they can piece together the puzzle.
Like the first 2 books, this is a cute, cozy, easy read. I absolutely love the characters and found myself chuckling out loud at Cordelia’s sassy sarcastic quips. This series should definitely be read in order, but there is a lot of recapping to get the reader caught up. At times the repetitiveness was a little annoying/unnecessary, but many times it was helpful since it’s been 1-2 years since I’ve read the other books.
Thank you to NetGalley and St. Martin's Press for this ARC. This review will be shared on NetGalley and Goodreads.
Pub Date Oct 20 2026
(A Ruby and Cordelia Mystery: Book 3)
My favorite non-spooky ghost series is back! Cordelia (a ghost) and Ruby (the tenant who took over her apartment) continue to team up as an unusual duo to solve mysteries. Now is the time to solve Cordelia’s own murder. Cordelia can walk through walls, teleport, and blow up electronics, but she can’t remember the hours/days leading up to her death. With Ruby’s help, they can piece together the puzzle.
Like the first 2 books, this is a cute, cozy, easy read. I absolutely love the characters and found myself chuckling out loud at Cordelia’s sassy sarcastic quips. This series should definitely be read in order, but there is a lot of recapping to get the reader caught up. At times the repetitiveness was a little annoying/unnecessary, but many times it was helpful since it’s been 1-2 years since I’ve read the other books.
Thank you to NetGalley and St. Martin's Press for this ARC. This review will be shared on NetGalley and Goodreads.
Pub Date Oct 20 2026
Review of advance copy received from NetGalley
The Key to a Killer is the 3rd fun book in Olivia Blacke's Ruby and Cordelia Mysteries and it is really enjoyable. Ruby's roommate is Cordelia who is a ghost. Cordelia died under suspicious circumstances and Ruby moved into the apartment and learned to live and communicate with Cordelia. When Cordelia died it was labeled a suicide and she can't remember what happened. Ruby and Cordelia begin to investigate to figure out what happened when Cordelia died. There are a few suspects and I wasn't sure who the culprit was. Cordelia's brother Ian shows up and keeps the story interesting. Ruby works for TrendCelerate and Cordelia worked there when she was alive and dated one.of the bosses. There are rumors that Cordelia was involved with helping their rival. There is a lot going on to keep Ruby and Cordelia busy! The story has humor and friendship and the mystery of Cordelia's death is solved. I really enjoyed this book! #TheKeyToAKiller #RubyAndCordeliaMysteries #MinotaurBooks #NetGalley
Read
July 27, 2026Thank you to the author, publisher and Net Galley for providing an ARC.
This is a cozy mystery, book 3 in a series. I believe I read book 1, but I think I missed book 2, so I did feel like I needed some more details, but it wasn't terrible as a stand alone.
For a cozy mystery, the clues are logical, the characters feel real and the dialog is realistic. However, for books set in Boston, I didn't feel like I was actually in that area. There was quite a bit of reference to places and landmarks, but that's not Boston. This book felt like it could be transplanted to any other city in the USA and it would make as much sense.
Cozy mystery lovers will enjoy this.
2.5 stars.
This is a cozy mystery, book 3 in a series. I believe I read book 1, but I think I missed book 2, so I did feel like I needed some more details, but it wasn't terrible as a stand alone.
For a cozy mystery, the clues are logical, the characters feel real and the dialog is realistic. However, for books set in Boston, I didn't feel like I was actually in that area. There was quite a bit of reference to places and landmarks, but that's not Boston. This book felt like it could be transplanted to any other city in the USA and it would make as much sense.
Cozy mystery lovers will enjoy this.
2.5 stars.
Review of advance copy received from NetGalley
This is the third book in the series, don't read this review because there could be minor spoilers. I liked the other two books in this series, but this one just didn't vibe with me. Most of the book is spent rehashing what we already know from the other books. I felt like I was skipping pages just to get to the plot of this book. When we finally start uncovering more plot, it feels incredibly rushed. I like a good red herring, but this felt like the author threw a twist in there just for fun. It's like a Marvel movie, they don't want you to guess the spoiler, so they just make something up that's crazy. I feel like it's better storytelling when you can follow the plot to a logical conclusion, instead of a c plot coming out of nowhere to slap you in the face.
The plot of this book is supposed to be following how Cordelia really died. Again, so much of Cordelia and Ruby investigating in this book is really just rehashing the last two books. I found myself flipping through pages, just wanting to get to the big reveal. I could have done with more character development for Cordelia's brother and Tosh, Ruby's kind of love interest. There was more Cordelia and Adam (Cordelia's old boss and married lover) backstory revealed, and Cordelia gets more of her memories back from the events leading up to her death. I still felt like these parts were rushed and too much of the book was just filler.
The last act of the book just felt like an accident. There is a running plot throughout this book about burglaries in the building Ruby/Cordelia live in. While Ruby is sort of investigating this, it seems like it would have been easily solved if Cordelia, you know the ghost, would have just staked out the hallways to catch the perp. I just wasn't satisfied with how the plot rolled out. I will likely read the next in the series and I hope it's more satisfying than this.
Thanks to NetGalley and Minotaur for the advanced copy, all opinions are my own.
The plot of this book is supposed to be following how Cordelia really died. Again, so much of Cordelia and Ruby investigating in this book is really just rehashing the last two books. I found myself flipping through pages, just wanting to get to the big reveal. I could have done with more character development for Cordelia's brother and Tosh, Ruby's kind of love interest. There was more Cordelia and Adam (Cordelia's old boss and married lover) backstory revealed, and Cordelia gets more of her memories back from the events leading up to her death. I still felt like these parts were rushed and too much of the book was just filler.
The last act of the book just felt like an accident. There is a running plot throughout this book about burglaries in the building Ruby/Cordelia live in. While Ruby is sort of investigating this, it seems like it would have been easily solved if Cordelia, you know the ghost, would have just staked out the hallways to catch the perp. I just wasn't satisfied with how the plot rolled out. I will likely read the next in the series and I hope it's more satisfying than this.
Thanks to NetGalley and Minotaur for the advanced copy, all opinions are my own.
May 6, 2026
I picked up the first book in this series because I liked the cover. I’m so glad I did because I’ve really enjoyed this cozy, quirky, charming series. Ruby and Cordelia are such an unlikely but dynamic duo.
Review of advance copy received from NetGalley
This originally appeared at The Irresponsible Reader. If you like this post, you might like others on that site. Consider checking it out!
---
WHAT'S THE KEY TO A KILLER ABOUT?
With two solved murders under their belt, it's time for Ruby and Cordelia to focus on one closer to home—very close to home. It's time to talk about Cordelia's murder.
Cordelia begins to remember more about that fatal night—which starts to point them in the right direction.
All they have to do is hope her memories continue to come back, while they're distracted by industrial espionage, marital difficulties (obviously, not either of theirs), Cordelia's brother, Ruby's budding romance, workplace struggles, new ghost abilities (better said, Cordelia learning about abilities she had), a series of break-ins at their apartment building, some questionable political moves, a persistent journalist, and a few other things. Most of which could point to the solution to their puzzle. But might not.
WHY DID I PICK THIS UP? WHY DID I KEEP READING?
I grabbed this to read because I'd read the first two books in the series and had to find out what happened next. I've been curious (as Blacke wanted the reader to be) about Cordelia's murder since her first book. It wasn't too long before Blacke made it clear to the reader that she didn't die accidentally or by her own hand (no matter what Cordelia's ghost might have thought), so I just had to know whodunit.
Also, I'd read Blacke's last 5 books, and have found her to be a completely reliable author, and I'm now predisposed to pick up something with her name on it without much thought.
I kept going because I like the characters, first and foremost, and enjoy spending time with them. Curiosity (see the opening paragraph of this section) was obviously a driving force, too. But Blacke kept putting them in interesting circumstances, things that raised more questions than they answered, and watching the two bounce around from red herring to red herring to a thing that actually matters, just not in the way they thought...Blacke got everything right this time.
WHAT DOES THIS BOOK TELL US ABOUT HUMANITY?
I think The Key to a Killer—like the rest of the series, actually—has two important themes about humanity. The first is trust. Extending trust to the right people, cutting off that trust when we should, and then relying on those we've trusted. If we act like islands (think Simon and Garfunkel's "I Am a Rock"), we flail. Both Ruby and Cordelia are proofs for that.
The second is the need to not be alone. Ruby needs people to keep her out of her head and for safety. Cordelia needs people to care for, to help her not make self-destructive choices, to just be around. The isolation she wrapped herself in wasn't good for her. Ruby was likely headed in a similar direction before she and her new roommate got together.
I guess really, both of those could be summed up in a need for community of some sort—the people in their building, their coworkers, fellow ghosts, family. Now, it's clear that not everyone in the building or at work should be depended on—and ghosts can be less than reliable (just like the living)—but in actual community is where humans, living or not, thrive.
SO, WHAT DID I THINK ABOUT THE KEY TO A KILLER?
I do think the first in the series, A New Lease on Death was more entertaining—the humor was a bit more pronounced, the fun of watching the two figure each other out, and so on—made for more fun. Death at the Door was a bit more tense, with more implied danger. But Blacke topped the others here with heart and intrigue—the threat of violence seemed both more pressing and less likely (I think this has to do with the number of allies that Ruby has picked up by this time). She took everything she's done so far and kicked it up a notch or two (except maybe the humor—but that could be in an "eye of the beholder" situation this was more about earnest effort), as she should. The result is a novel that's just a little bit more satisfying than its predecessors.
I'm assuming that this is the end of the road for this duo. I'd be very pleased to find out that I'm wrong, but it feels like this Blacke has tied up enough that she can leave them to un-recorded adventures. If that's the case, this is a satisfying end-point for the pair. We see them in good places, with a lot tied up, some good closure on lingering questions about Cordelia's life (beyond the question of "who killed her")—and Ruby in a good place, too.
Obviously, learning more about Cordelia's final days gives the reader a lot to chew on. Without wanting to give too much away, learning what we do about her married boyfriend is rather revealing—and I'm glad Blacke went the way she did with that. In the end, she's a more complex and flawed character than she seemed to be when we first met her spectral form.
There's one clue that took Ruby frustratingly long to figure out—and I'm less than happy with one of her subplots was left (there's something to be explored if Blacke goes for a fourth book). But overall, the arc she's been on is very well done. Honestly, those two points are my only complaints about this book.
I don't know if this is the best book to jump into things with—but it would work for someone looking for a ghosty-cozyish mystery for October. I think you'd be better off with three of the books to give you a solid ghosty story from the beginning. Obviously, I think most of the audience for this will be those like me who just want the big question about Cordelia answered and who look forward to the adventures up to that reveal (which was done so nicely).
I'm looking forward to whatever Blacke has coming next, too. I think most readers of this book will be, too.
Disclaimer: I received this eARC from St. Martin's Press via NetGalley—my thanks to both for this. This post contains my honest opinion about a book I chose to read.
---
WHAT'S THE KEY TO A KILLER ABOUT?
With two solved murders under their belt, it's time for Ruby and Cordelia to focus on one closer to home—very close to home. It's time to talk about Cordelia's murder.
Cordelia begins to remember more about that fatal night—which starts to point them in the right direction.
All they have to do is hope her memories continue to come back, while they're distracted by industrial espionage, marital difficulties (obviously, not either of theirs), Cordelia's brother, Ruby's budding romance, workplace struggles, new ghost abilities (better said, Cordelia learning about abilities she had), a series of break-ins at their apartment building, some questionable political moves, a persistent journalist, and a few other things. Most of which could point to the solution to their puzzle. But might not.
WHY DID I PICK THIS UP? WHY DID I KEEP READING?
I grabbed this to read because I'd read the first two books in the series and had to find out what happened next. I've been curious (as Blacke wanted the reader to be) about Cordelia's murder since her first book. It wasn't too long before Blacke made it clear to the reader that she didn't die accidentally or by her own hand (no matter what Cordelia's ghost might have thought), so I just had to know whodunit.
Also, I'd read Blacke's last 5 books, and have found her to be a completely reliable author, and I'm now predisposed to pick up something with her name on it without much thought.
I kept going because I like the characters, first and foremost, and enjoy spending time with them. Curiosity (see the opening paragraph of this section) was obviously a driving force, too. But Blacke kept putting them in interesting circumstances, things that raised more questions than they answered, and watching the two bounce around from red herring to red herring to a thing that actually matters, just not in the way they thought...Blacke got everything right this time.
WHAT DOES THIS BOOK TELL US ABOUT HUMANITY?
I think The Key to a Killer—like the rest of the series, actually—has two important themes about humanity. The first is trust. Extending trust to the right people, cutting off that trust when we should, and then relying on those we've trusted. If we act like islands (think Simon and Garfunkel's "I Am a Rock"), we flail. Both Ruby and Cordelia are proofs for that.
The second is the need to not be alone. Ruby needs people to keep her out of her head and for safety. Cordelia needs people to care for, to help her not make self-destructive choices, to just be around. The isolation she wrapped herself in wasn't good for her. Ruby was likely headed in a similar direction before she and her new roommate got together.
I guess really, both of those could be summed up in a need for community of some sort—the people in their building, their coworkers, fellow ghosts, family. Now, it's clear that not everyone in the building or at work should be depended on—and ghosts can be less than reliable (just like the living)—but in actual community is where humans, living or not, thrive.
SO, WHAT DID I THINK ABOUT THE KEY TO A KILLER?
I do think the first in the series, A New Lease on Death was more entertaining—the humor was a bit more pronounced, the fun of watching the two figure each other out, and so on—made for more fun. Death at the Door was a bit more tense, with more implied danger. But Blacke topped the others here with heart and intrigue—the threat of violence seemed both more pressing and less likely (I think this has to do with the number of allies that Ruby has picked up by this time). She took everything she's done so far and kicked it up a notch or two (except maybe the humor—but that could be in an "eye of the beholder" situation this was more about earnest effort), as she should. The result is a novel that's just a little bit more satisfying than its predecessors.
I'm assuming that this is the end of the road for this duo. I'd be very pleased to find out that I'm wrong, but it feels like this Blacke has tied up enough that she can leave them to un-recorded adventures. If that's the case, this is a satisfying end-point for the pair. We see them in good places, with a lot tied up, some good closure on lingering questions about Cordelia's life (beyond the question of "who killed her")—and Ruby in a good place, too.
Obviously, learning more about Cordelia's final days gives the reader a lot to chew on. Without wanting to give too much away, learning what we do about her married boyfriend is rather revealing—and I'm glad Blacke went the way she did with that. In the end, she's a more complex and flawed character than she seemed to be when we first met her spectral form.
There's one clue that took Ruby frustratingly long to figure out—and I'm less than happy with one of her subplots was left (there's something to be explored if Blacke goes for a fourth book). But overall, the arc she's been on is very well done. Honestly, those two points are my only complaints about this book.
I don't know if this is the best book to jump into things with—but it would work for someone looking for a ghosty-cozyish mystery for October. I think you'd be better off with three of the books to give you a solid ghosty story from the beginning. Obviously, I think most of the audience for this will be those like me who just want the big question about Cordelia answered and who look forward to the adventures up to that reveal (which was done so nicely).
I'm looking forward to whatever Blacke has coming next, too. I think most readers of this book will be, too.
Disclaimer: I received this eARC from St. Martin's Press via NetGalley—my thanks to both for this. This post contains my honest opinion about a book I chose to read.
Review of advance copy received from Author
Thank you to Minotaur books and the author for the opportunity to read in advance and provide an honest review!
Those who’ve been invested in Ruby and Cordelia’s antics - great news, we finally get some long-awaited answers about what happened to Cordy!
It gave this story a little more emotional weight while still keeping everything I’ve loved about this series intact. And if this is the ending, I really do think it wrapped everything up on such a good note. But also… I love these ladies so much, and I am not quite ready to be done spending time with them!
Officially on the record: If I ever die or meet an untimely demise, I want these ladies on the case.
Here’s what I loved about book 3 (& series!):
- The rated-R humor. The author does such a great job of folding serious content into these stories without ever making them feel overwhelmingly dark. Ruby and Cordelia interact with some seedy people and end up in some very precarious situations, but there’s always enough humor and care between the characters to balance it all out. Somehow all of the murder, trauma, and questionable life choices remain extremely easy to digest.
- Ruby and Cordelia’s relationship. I love them together so much. At this point, it’s easy to forget how completely unhinged the premise actually is because, sure, who wouldn’t casually have a ghost roommate they solve crimes with while also investigating said ghost’s suspected suicide? All in all, there are some really heartfelt moments between them in this one, and I loved seeing how much they’ve both grown through this very bizarre life/afterlife they’ve built together.
- More Ian! I really liked having him more involved and getting more of his perspective, especially when it came to his relationship with Ruby. Throughout the series, we’ve spent so much time inside Ruby’s head hearing about how much she did for her brother growing up, so there was something really sweet about finally getting more of his memories of their childhood and the way he remembers his sister. Those moments added a lot of heart and more umph behind Cordelia’s character.
- The progression of the series. We’ve watched Ruby really come into her own and learn how to “adult” — with Cordelia’s help, obviously — while Cordelia has been figuring out an entirely different kind of existence. This book felt like both of those journeys came into sharper focus. Ruby feels more settled in herself, and Cordelia finally has to confront some hard truths and long-awaited answers about her life and death.
- The Ghost Rules. I love all the little details about what being a ghost actually means in this world — especially watching Cordelia figure out what she can and can’t do, how technology works around her, and all the strange limitations and loopholes that come with the afterlife. It’s such a fun part of the series, and I’ve loved seeing the author continue to expand on it.
More than anything, I finished this one realizing just how much fun I’ve had with these characters and this whole wonderfully strange storyline. It has been such a joy watching Ruby and Cordelia stumble their way through murders, ghosts, adulthood, friendship, and everything else thrown at them.
So if this really is the end, I’m happy with where we’re leaving them. It feels like a fitting close to a series that has been weird, warm, funny, heartfelt, and so easy to love.
But if Ruby and Cordelia decide there’s one more mystery worth chasing? We ride at dawn!
Those who’ve been invested in Ruby and Cordelia’s antics - great news, we finally get some long-awaited answers about what happened to Cordy!
It gave this story a little more emotional weight while still keeping everything I’ve loved about this series intact. And if this is the ending, I really do think it wrapped everything up on such a good note. But also… I love these ladies so much, and I am not quite ready to be done spending time with them!
Officially on the record: If I ever die or meet an untimely demise, I want these ladies on the case.
Here’s what I loved about book 3 (& series!):
- The rated-R humor. The author does such a great job of folding serious content into these stories without ever making them feel overwhelmingly dark. Ruby and Cordelia interact with some seedy people and end up in some very precarious situations, but there’s always enough humor and care between the characters to balance it all out. Somehow all of the murder, trauma, and questionable life choices remain extremely easy to digest.
- Ruby and Cordelia’s relationship. I love them together so much. At this point, it’s easy to forget how completely unhinged the premise actually is because, sure, who wouldn’t casually have a ghost roommate they solve crimes with while also investigating said ghost’s suspected suicide? All in all, there are some really heartfelt moments between them in this one, and I loved seeing how much they’ve both grown through this very bizarre life/afterlife they’ve built together.
- More Ian! I really liked having him more involved and getting more of his perspective, especially when it came to his relationship with Ruby. Throughout the series, we’ve spent so much time inside Ruby’s head hearing about how much she did for her brother growing up, so there was something really sweet about finally getting more of his memories of their childhood and the way he remembers his sister. Those moments added a lot of heart and more umph behind Cordelia’s character.
- The progression of the series. We’ve watched Ruby really come into her own and learn how to “adult” — with Cordelia’s help, obviously — while Cordelia has been figuring out an entirely different kind of existence. This book felt like both of those journeys came into sharper focus. Ruby feels more settled in herself, and Cordelia finally has to confront some hard truths and long-awaited answers about her life and death.
- The Ghost Rules. I love all the little details about what being a ghost actually means in this world — especially watching Cordelia figure out what she can and can’t do, how technology works around her, and all the strange limitations and loopholes that come with the afterlife. It’s such a fun part of the series, and I’ve loved seeing the author continue to expand on it.
More than anything, I finished this one realizing just how much fun I’ve had with these characters and this whole wonderfully strange storyline. It has been such a joy watching Ruby and Cordelia stumble their way through murders, ghosts, adulthood, friendship, and everything else thrown at them.
So if this really is the end, I’m happy with where we’re leaving them. It feels like a fitting close to a series that has been weird, warm, funny, heartfelt, and so easy to love.
But if Ruby and Cordelia decide there’s one more mystery worth chasing? We ride at dawn!
Review of advance copy received from NetGalley
How can solving a murder be a let down?
Ruby Young and her ghostly roommate, Cordelia Graves, have worked together to solve two murders: one at their apartment building and one at their job. Now Ruby and Cordelia have finally decided it was time to solve the most important investigation--who killed Cordelia.
Ruby not only moved into Cordelia's apartment but, with Cordelia's prompting, Ruby took over her receptionist job at TrendCelebrate. This all leaves Ruby perfectly set up to investigate everyone in Cordelia's life just before someone took it--because it certainly wasn't Cordelia no matter what her death certificate might say.
It also couldn't have been Cordelia's little brother, Ian, who has just been released from prison. Ian now knows that his sister is haunting her old apartment so Ian has taken to breaking into the apartment looking for clues or notes that Cordelia might have left for him.
The list of suspects on their fridge keeps getting longer and each one might just have had a perfect reason to need to get rid of Cordelia. There are clues that Ruby and Cordelia have uncovered over the last year, including the mysterious man who left with a computer case the night Cordelia died. Post-mortem Cordelia was accused of selling the company's new software to the competition. Did she, or was her computer stolen by her murderer? Cordelia was having an affair with her married boss, and she isn't the only one. Did her lover or his other lover have anything to do with her death or was it the jealous wife?
Was it luck that Ruby and Cordelia were able to solve the other murders or will solving this one put a target on Ruby's back? This is the most important investigation and also the most dangerous.
THOUGHTS:
I don't generally reach for cozy mysteries but I find I like these Ruby/Cordelia mysteries. Of course when you have a ghost solving murders, one of those murders that you want them to solve is their own. Duh! I have been waiting for them to solve the big mystery of Cordelia's death. There were a lot of possible suspects from Cordelia's life who might have turned on her. They have been discussing each possibility and building cases against each suspect of the last few books. Each one sounding more and more plausible.
While I was reading, I couldn't stop trying to figure out which one on their list was most likely responsible. Cordelia couldn't remember the day of her death but as the story progressed, she got longer and longer flashes of what had happened to her that day, which in fact brought even more possible suspects for the list. I couldn't wait to unmask the villain, answer all they how's and why's and solve all the mysteries surrounding her death.
So about that...after all the investigating we do find out who killed Cordelia. Was it all I hoped it would be?...No. There were still one or two unanswered questions but we do know what happened the night Cordelia died and I have to say I found that answer unsatisfying and I would be pissed to be dead over such a stupid reason. I am sad for Cordelia and even thought we now know who is responsible, she still doesn't get to come back and continue where she left off.
I like Ruby and Cordelia. I will absolutely be checking out the next book although I think a part of me will always be sad about what happened to Cordelia.
Ruby Young and her ghostly roommate, Cordelia Graves, have worked together to solve two murders: one at their apartment building and one at their job. Now Ruby and Cordelia have finally decided it was time to solve the most important investigation--who killed Cordelia.
Ruby not only moved into Cordelia's apartment but, with Cordelia's prompting, Ruby took over her receptionist job at TrendCelebrate. This all leaves Ruby perfectly set up to investigate everyone in Cordelia's life just before someone took it--because it certainly wasn't Cordelia no matter what her death certificate might say.
It also couldn't have been Cordelia's little brother, Ian, who has just been released from prison. Ian now knows that his sister is haunting her old apartment so Ian has taken to breaking into the apartment looking for clues or notes that Cordelia might have left for him.
The list of suspects on their fridge keeps getting longer and each one might just have had a perfect reason to need to get rid of Cordelia. There are clues that Ruby and Cordelia have uncovered over the last year, including the mysterious man who left with a computer case the night Cordelia died. Post-mortem Cordelia was accused of selling the company's new software to the competition. Did she, or was her computer stolen by her murderer? Cordelia was having an affair with her married boss, and she isn't the only one. Did her lover or his other lover have anything to do with her death or was it the jealous wife?
Was it luck that Ruby and Cordelia were able to solve the other murders or will solving this one put a target on Ruby's back? This is the most important investigation and also the most dangerous.
THOUGHTS:
I don't generally reach for cozy mysteries but I find I like these Ruby/Cordelia mysteries. Of course when you have a ghost solving murders, one of those murders that you want them to solve is their own. Duh! I have been waiting for them to solve the big mystery of Cordelia's death. There were a lot of possible suspects from Cordelia's life who might have turned on her. They have been discussing each possibility and building cases against each suspect of the last few books. Each one sounding more and more plausible.
While I was reading, I couldn't stop trying to figure out which one on their list was most likely responsible. Cordelia couldn't remember the day of her death but as the story progressed, she got longer and longer flashes of what had happened to her that day, which in fact brought even more possible suspects for the list. I couldn't wait to unmask the villain, answer all they how's and why's and solve all the mysteries surrounding her death.
So about that...after all the investigating we do find out who killed Cordelia. Was it all I hoped it would be?...No. There were still one or two unanswered questions but we do know what happened the night Cordelia died and I have to say I found that answer unsatisfying and I would be pissed to be dead over such a stupid reason. I am sad for Cordelia and even thought we now know who is responsible, she still doesn't get to come back and continue where she left off.
I like Ruby and Cordelia. I will absolutely be checking out the next book although I think a part of me will always be sad about what happened to Cordelia.
Review of advance copy received from Publisher
I must admit that I wasn't quite certain what to expect when I took the book The Key to a Killer, particularly as it is the third in the Ruby and Cordelia Mysteries series and I had not read the first two. Nevertheless, I was pleasantly surprised by how quickly I got into the story. Olivia Blacke handles the inclusion of important details from the earlier books very well, so it doesn't feel like she's merely summarizing. I never felt lost or confused, which is no small achievement considering that you're entering the series so far along.
Shall we discuss Cordelia? I really loved her! Though she doesn't have a physical body, she makes up for it with a vibrant personality. She is opinionated, quick-witted, and has just the right amount of attitude, so her conversations with Ruby are completely entertaining. Their banter is easily one of my favorite aspects of the book. I enjoyed how their friendship has developed into something that feels truly affectionate, even when they argue. In fact, Cordelia alone is the reason why I want to get my hands on books one and two as soon as possible. I really feel as though I've been missing out!
The mystery was also quite entertaining. This time Ruby and Cordelia are looking into Cordelia's own death, which gives their usual investigations a more personal touch. I thought Blacke handled the red herrings brilliantly; whenever I thought I had worked out what was going on, another clue would appear and send me down a completely new path. The story has a great many twists, and that surprise at the end? I certainly didn't expect it! It's one of the things I enjoy about a mystery—that it still manages to surprise me after having spent most of the book trying to outwit the author.
The only real thing I didn't like was that I would have preferred a bit more suspense. I realize this is a cozy mystery, so I don't expect the kind of tension found in a psychological thriller. That said, since the investigation is so personal, I feel there should have been ways to add a bit more urgency. The pacing was also a bit uneven; in some sections I was eagerly turning the pages, but in others it slowed down so much that I wished the action would pick up again.
Still, I really enjoyed this one! The humor, the friendship, and the clever misdirection more than compensated for the slower sections. I now have two more books to include on my TBR, and I'm choosing to see that as a positive rather than yet another instance of my total inability to keep that list in check.
If you like cozy mysteries with odd characters, paranormal elements, and a friendship that could be more enjoyable than the murder investigation itself, you should definitely get The Key to a Killer. Yes, you can start with book three, but I think you'll end up wanting to go back and start at the beginning!
🌼 Floral Verdict: A Daisy
It's a pleasant, easygoing paranormal cozy mystery with excellent character chemistry, some clever red herrings, and a ghost who really steals the spotlight.
Shall we discuss Cordelia? I really loved her! Though she doesn't have a physical body, she makes up for it with a vibrant personality. She is opinionated, quick-witted, and has just the right amount of attitude, so her conversations with Ruby are completely entertaining. Their banter is easily one of my favorite aspects of the book. I enjoyed how their friendship has developed into something that feels truly affectionate, even when they argue. In fact, Cordelia alone is the reason why I want to get my hands on books one and two as soon as possible. I really feel as though I've been missing out!
The mystery was also quite entertaining. This time Ruby and Cordelia are looking into Cordelia's own death, which gives their usual investigations a more personal touch. I thought Blacke handled the red herrings brilliantly; whenever I thought I had worked out what was going on, another clue would appear and send me down a completely new path. The story has a great many twists, and that surprise at the end? I certainly didn't expect it! It's one of the things I enjoy about a mystery—that it still manages to surprise me after having spent most of the book trying to outwit the author.
The only real thing I didn't like was that I would have preferred a bit more suspense. I realize this is a cozy mystery, so I don't expect the kind of tension found in a psychological thriller. That said, since the investigation is so personal, I feel there should have been ways to add a bit more urgency. The pacing was also a bit uneven; in some sections I was eagerly turning the pages, but in others it slowed down so much that I wished the action would pick up again.
Still, I really enjoyed this one! The humor, the friendship, and the clever misdirection more than compensated for the slower sections. I now have two more books to include on my TBR, and I'm choosing to see that as a positive rather than yet another instance of my total inability to keep that list in check.
If you like cozy mysteries with odd characters, paranormal elements, and a friendship that could be more enjoyable than the murder investigation itself, you should definitely get The Key to a Killer. Yes, you can start with book three, but I think you'll end up wanting to go back and start at the beginning!
🌼 Floral Verdict: A Daisy
It's a pleasant, easygoing paranormal cozy mystery with excellent character chemistry, some clever red herrings, and a ghost who really steals the spotlight.
Review of advance copy received from Publisher
First, a big THANK YOU to my book dealer at St. Martin’s Press. I can never refuse her offers of free ARCs, and I am more than delighted to add any Olivia Blacke book to my teetering TBR pile.
In this third installment of the Ruby and Cordelia Mysteries, Ruby decides to tackle the cold case of her roommate’s untimely death. Let me back up a bit. This series features two equally lovable protagonists: Ruby (the quirky, broke Gen Z girly) and Cordelia (the murdered woman who now haunts Ruby’s humble abode (a rundown Boston apartment). Love the premise? Me too!!!
Here are my thoughts:
The gist: This mystery centers on a vexing cold case: Cordelia’s murder, which the lazy, useless cops carelessly wrote off as a suicide. It’s up to Ruby—our hapless, disheveled amateur detective—to dig into the nefarious underbelly of a shady tech company (also her workplace’s rival) and figure out what’s going on with Cordelia’s former paramour… who just so happens to be Ruby’s boss. You see, Cordelia used to work there too, and she had an uncanny gift for writing and deciphering code. Messy, right?
Thoughts on the characters: Unlike your typical “Mary Sue” cozy mystery sleuths, Ruby and Cordelia are endearingly flawed and complex. Ruby comes from a loving home and is still new to adulting, while Cordelia’s past is steeped in abuse, neglect, and even homelessness. Together, they form a mother‑daughter bond that warms my hardened heart. I adore how Cordelia shoplifts grown‑up clothes for Ruby and keeps watch over her. It’s just so dang sweet! Ugh! I want a motherly ghost roomie!!!
The setting: I usually read cozies set in charming resort towns, but this gritty Boston backdrop really works for the storyline. It’s gross, dirty, loud, and crime‑ridden—adding an extra layer of danger to the story. There’s also a subplot involving break‑ins at Ruby and Cordelia’s apartment building that may tie into the cold case. Such intrigue!
The backstories: This book finally reveals Cordelia’s pre‑ghostly life. As Ruby hunts down clues, Cordelia experiences flashbacks of her corporeal days, giving us insight into her upbringing, her brother’s path to prison (we’ll get to him later), and her… questionable romantic choices. This lady had a lot going on.
The romance: We’ve got a bit of a love triangle brewing between Ruby, her good guy neighbor (who works at the rival tech company), and Cordelia’s delinquent brother Ian, freshly out of prison. We learn plenty about both suitors, and boy does Ruby have a lot on her plate! Oh, to be young and in love again…sigh.
Overall: The Ruby and Cordelia Mysteries remains in my top ten (maybe even top five!) of all-time favorite cozy series, and this book did not disappoint. We finally get answers to Cordelia’s mysterious past and the tech companies’ hidden secrets. I was a little misty-eyed when it ended, but the author leaves just enough room for a few more books in the series. Here’s hoping!
In this third installment of the Ruby and Cordelia Mysteries, Ruby decides to tackle the cold case of her roommate’s untimely death. Let me back up a bit. This series features two equally lovable protagonists: Ruby (the quirky, broke Gen Z girly) and Cordelia (the murdered woman who now haunts Ruby’s humble abode (a rundown Boston apartment). Love the premise? Me too!!!
Here are my thoughts:
The gist: This mystery centers on a vexing cold case: Cordelia’s murder, which the lazy, useless cops carelessly wrote off as a suicide. It’s up to Ruby—our hapless, disheveled amateur detective—to dig into the nefarious underbelly of a shady tech company (also her workplace’s rival) and figure out what’s going on with Cordelia’s former paramour… who just so happens to be Ruby’s boss. You see, Cordelia used to work there too, and she had an uncanny gift for writing and deciphering code. Messy, right?
Thoughts on the characters: Unlike your typical “Mary Sue” cozy mystery sleuths, Ruby and Cordelia are endearingly flawed and complex. Ruby comes from a loving home and is still new to adulting, while Cordelia’s past is steeped in abuse, neglect, and even homelessness. Together, they form a mother‑daughter bond that warms my hardened heart. I adore how Cordelia shoplifts grown‑up clothes for Ruby and keeps watch over her. It’s just so dang sweet! Ugh! I want a motherly ghost roomie!!!
The setting: I usually read cozies set in charming resort towns, but this gritty Boston backdrop really works for the storyline. It’s gross, dirty, loud, and crime‑ridden—adding an extra layer of danger to the story. There’s also a subplot involving break‑ins at Ruby and Cordelia’s apartment building that may tie into the cold case. Such intrigue!
The backstories: This book finally reveals Cordelia’s pre‑ghostly life. As Ruby hunts down clues, Cordelia experiences flashbacks of her corporeal days, giving us insight into her upbringing, her brother’s path to prison (we’ll get to him later), and her… questionable romantic choices. This lady had a lot going on.
The romance: We’ve got a bit of a love triangle brewing between Ruby, her good guy neighbor (who works at the rival tech company), and Cordelia’s delinquent brother Ian, freshly out of prison. We learn plenty about both suitors, and boy does Ruby have a lot on her plate! Oh, to be young and in love again…sigh.
Overall: The Ruby and Cordelia Mysteries remains in my top ten (maybe even top five!) of all-time favorite cozy series, and this book did not disappoint. We finally get answers to Cordelia’s mysterious past and the tech companies’ hidden secrets. I was a little misty-eyed when it ended, but the author leaves just enough room for a few more books in the series. Here’s hoping!
October 12, 2026
The Key to a Killer is book 3 in Olivia Blacke's The Ruby and Cordelia Mysteries, but it is easily read as a standalone novel.
In The Key to a Killer, Ruby and her ghostly roommate ,Cordelia, turn their attention to Cordelia's death which was ruled to be a suicide, but Cordelia insists she was murdered, only she can't remember what happened on the day of her death or leading up to it.
The story is told in alternating points of view, from the perspectives of Ruby and Cordelia. Occasionally, it can be confusing when you first start the next chapter, but for the most part it’s done well and it keeps the story interesting.
I read the second book in this series and it had left me with a number of questions, and some curiosity over some of the characters in that book. I’m happy to say that many of my questions were answered, and I got to know some of the characters better in book three. I especially grew to like Cordelia’s younger brother, Ian, who appeared to be a bit of a troublemaker, and ne’er-do-well.
Like the previous book there was quite a large cast of characters to eliminate as suspects, and a number of motives to complicate things as well. This combination kept me guessing well into the book, and all of the characters and motives felt plausible. There were several times when I thought I had worked out the mystery of Cordelia’s death, but I didn’t get it right until right before the truth was revealed.
The only thing that still bothered me about this series, not just this particular book, was how Cordelia communicated with Ruby. She doesn’t appear to have an issue interacting with items in the real world so I still don’t understand why she can’t use a pen and paper instead of refrigerator magnets for communicating. Maybe it was explained in book one and I just missed it.
I enjoyed The Key to a Killer. I think most people who enjoy cozy mysteries will enjoy it, especially if you enjoy a mystery with a paranormal twist.
I received an advance review copy for free, and I am leaving this review voluntarily.
In The Key to a Killer, Ruby and her ghostly roommate ,Cordelia, turn their attention to Cordelia's death which was ruled to be a suicide, but Cordelia insists she was murdered, only she can't remember what happened on the day of her death or leading up to it.
The story is told in alternating points of view, from the perspectives of Ruby and Cordelia. Occasionally, it can be confusing when you first start the next chapter, but for the most part it’s done well and it keeps the story interesting.
I read the second book in this series and it had left me with a number of questions, and some curiosity over some of the characters in that book. I’m happy to say that many of my questions were answered, and I got to know some of the characters better in book three. I especially grew to like Cordelia’s younger brother, Ian, who appeared to be a bit of a troublemaker, and ne’er-do-well.
Like the previous book there was quite a large cast of characters to eliminate as suspects, and a number of motives to complicate things as well. This combination kept me guessing well into the book, and all of the characters and motives felt plausible. There were several times when I thought I had worked out the mystery of Cordelia’s death, but I didn’t get it right until right before the truth was revealed.
The only thing that still bothered me about this series, not just this particular book, was how Cordelia communicated with Ruby. She doesn’t appear to have an issue interacting with items in the real world so I still don’t understand why she can’t use a pen and paper instead of refrigerator magnets for communicating. Maybe it was explained in book one and I just missed it.
I enjoyed The Key to a Killer. I think most people who enjoy cozy mysteries will enjoy it, especially if you enjoy a mystery with a paranormal twist.
I received an advance review copy for free, and I am leaving this review voluntarily.
Review of advance copy received from NetGalley
Review of Uncorrected Digital Galley
Cordelia Graves hears Ruby calling for help and hurries to assist her, only to discover that Ruby is in the bathroom, the one room in the apartment that Cordelia refuses to enter. That’s the room where, six months ago, she died.
But Cordelia forces herself to cross the threshold; Ruby needs help.
Ruby Young is deathly afraid of spiders. And there’s a spider on the bathtub faucet. Cordelia scoops him up and puts him outside on the window ledge.
Cordelia hadn’t wanted a roommate when she was alive, but now she and Ruby have come to a perfect partnership between ghost and breather.
And now, Ruby stuns Cordelia when she announces that it is time to find out who killed Cordelia . . . and why.
=========
Third in the author’s Ruby and Cordelia Mystery series, the book has sufficient backstory for readers new to the series and works well as a standalone. With the expected characters in place, and the strong relationship between Ruby and Cordelia, readers will be pulled into the telling of the tale from the outset.
The haunted apartment is sure to capture the reader’s imagination as the intriguing cozy mystery plays out. Some plot twists and a few unexpected surprises will keep readers guessing as the unfolding story heads toward a denouement that may be a total shock.
Readers who enjoy cozy mysteries, stories with a paranormal slant, and captivating mysteries will find much to appreciate here.
Highly recommended.
I received a free copy of this eBook from St. Martin’s Press / Minotaur Books and NetGalley and am voluntarily leaving this review.
#TheKeytoaKiller #NetGalley
Cordelia Graves hears Ruby calling for help and hurries to assist her, only to discover that Ruby is in the bathroom, the one room in the apartment that Cordelia refuses to enter. That’s the room where, six months ago, she died.
But Cordelia forces herself to cross the threshold; Ruby needs help.
Ruby Young is deathly afraid of spiders. And there’s a spider on the bathtub faucet. Cordelia scoops him up and puts him outside on the window ledge.
Cordelia hadn’t wanted a roommate when she was alive, but now she and Ruby have come to a perfect partnership between ghost and breather.
And now, Ruby stuns Cordelia when she announces that it is time to find out who killed Cordelia . . . and why.
=========
Third in the author’s Ruby and Cordelia Mystery series, the book has sufficient backstory for readers new to the series and works well as a standalone. With the expected characters in place, and the strong relationship between Ruby and Cordelia, readers will be pulled into the telling of the tale from the outset.
The haunted apartment is sure to capture the reader’s imagination as the intriguing cozy mystery plays out. Some plot twists and a few unexpected surprises will keep readers guessing as the unfolding story heads toward a denouement that may be a total shock.
Readers who enjoy cozy mysteries, stories with a paranormal slant, and captivating mysteries will find much to appreciate here.
Highly recommended.
I received a free copy of this eBook from St. Martin’s Press / Minotaur Books and NetGalley and am voluntarily leaving this review.
#TheKeytoaKiller #NetGalley
Review of advance copy received from Publisher
If you like: Nita Prose, Richard Osman, Robert Thorogood
Series: 3
Avail: 10/20
Rating: 🌕🌕🌕🌕
Genre: Cozy Mystery
Violence: 🪓🪓🪓
TW: Discussion of suicide & substance abuse, child neglect
The novels in this series alternate narrative between 20 YO Ruby & the forty-something dead woman who haunts her apartment, Cordelia. Blacke does a superb job—through tone, commentary, & cultural references—establishing a distinct POV between the 2 protagonists. The element I love most about these books is the world-building, i.e. the rules that dictate Cordelia’s afterlife. Under normal circumstances, Ruby can’t see or hear her dear departed roomie. And Cordy’s mere proximity fries electronics. So how can they solve crimes together? By communicating via magnetic fridge poetry, an etch-a-sketch & skittles a-la E.T., of course! This 3rd novel focuses on the mystery arc established at the series’ beginning: who murdered Cordelia & allowed her death to be ruled a suicide? Blacke effectively knots loose threads from the 2 previous mysteries while revealing more of Cordelia’s backstory & raising new questions, making for an engaging & dynamic storyline. There were times in this 3rd tale where “ghost rules” changed in service to story, though overall the author effectively explained the “misinterpretation.” I can forgive that when the mystery so successfully weaves seemingly unrelated plot points into a satisfying final solution. If you’re looking for a cozy with a unique premise, solid mysteries, & an amateur detecting duo who will make you smile, look no further than Olivia Blacke’s Ruby & Cordelia Mysteries.
Thank you to Minotaur for a gifted book in exchanged for an honest review.
Series: 3
Avail: 10/20
Rating: 🌕🌕🌕🌕
Genre: Cozy Mystery
Violence: 🪓🪓🪓
TW: Discussion of suicide & substance abuse, child neglect
The novels in this series alternate narrative between 20 YO Ruby & the forty-something dead woman who haunts her apartment, Cordelia. Blacke does a superb job—through tone, commentary, & cultural references—establishing a distinct POV between the 2 protagonists. The element I love most about these books is the world-building, i.e. the rules that dictate Cordelia’s afterlife. Under normal circumstances, Ruby can’t see or hear her dear departed roomie. And Cordy’s mere proximity fries electronics. So how can they solve crimes together? By communicating via magnetic fridge poetry, an etch-a-sketch & skittles a-la E.T., of course! This 3rd novel focuses on the mystery arc established at the series’ beginning: who murdered Cordelia & allowed her death to be ruled a suicide? Blacke effectively knots loose threads from the 2 previous mysteries while revealing more of Cordelia’s backstory & raising new questions, making for an engaging & dynamic storyline. There were times in this 3rd tale where “ghost rules” changed in service to story, though overall the author effectively explained the “misinterpretation.” I can forgive that when the mystery so successfully weaves seemingly unrelated plot points into a satisfying final solution. If you’re looking for a cozy with a unique premise, solid mysteries, & an amateur detecting duo who will make you smile, look no further than Olivia Blacke’s Ruby & Cordelia Mysteries.
Thank you to Minotaur for a gifted book in exchanged for an honest review.
Review of advance copy received from NetGalley
Thank you NetGalley, St. Martin's Press, and Olivia Blacke for a copy of the eARC. This book may have been the reason why I joined NetGalley after hearing about it from my friend.
Ruby and Cordelia are back again with their sleuthing. I love this pairing so much. They bring such joy and amusement because there's a big age gap on top of the fact that one is a ghost and the other is a human. I would very much like my own ghost roommate who shops for me and knows when to pass alcohol/coffee to me. It's extra delightful because Blacke actually does a really good job of playing into the age gap (i.e. Ruby can't read cursive).
I am so glad that we are onto our last book and finally trying to figure out who murdered Cordelia. The two have grown close and I think both have somewhat affected the other in a good way. Ruby has forced Cordelia into facing her past and Cordelia has influenced some of Ruby's tastes. I also love how Cordelia's brother, Ian, plays a bigger part in this story.
The book does somewhat give closure to all the topics brought up - Who killed Cordelia? What was the motive? What happened to Cordelia's 401k? What happened between TrendCelerate and CloudIndus? However, at the same time I feel like some topics left a bitter taste in my mouth because so many people were involved, but the ending was a little bland. Nonetheless, I still enjoyed this series and I'm hoping that one day Ruby may get a side story with romance.
Ruby and Cordelia are back again with their sleuthing. I love this pairing so much. They bring such joy and amusement because there's a big age gap on top of the fact that one is a ghost and the other is a human. I would very much like my own ghost roommate who shops for me and knows when to pass alcohol/coffee to me. It's extra delightful because Blacke actually does a really good job of playing into the age gap (i.e. Ruby can't read cursive).
I am so glad that we are onto our last book and finally trying to figure out who murdered Cordelia. The two have grown close and I think both have somewhat affected the other in a good way. Ruby has forced Cordelia into facing her past and Cordelia has influenced some of Ruby's tastes. I also love how Cordelia's brother, Ian, plays a bigger part in this story.
The book does somewhat give closure to all the topics brought up - Who killed Cordelia? What was the motive? What happened to Cordelia's 401k? What happened between TrendCelerate and CloudIndus? However, at the same time I feel like some topics left a bitter taste in my mouth because so many people were involved, but the ending was a little bland. Nonetheless, I still enjoyed this series and I'm hoping that one day Ruby may get a side story with romance.
September 8, 2026
The Key to a Killer by Olivia Blacke is the third book in the Ruby and Cordelia Mysteries series. I absolutely recommend this series! If you have not read the first two books I strongly suggest you read them first! The author does a great job of circling back to things that happened in the first two books so if you haven’t read them you get an idea of what has happened already.
Ruby and Cordelia are back in this third book and now the mystery that they are trying to solve is Cordelia’s death. Did she really take her own life or did something else happen? Ruby decides to run her own investigation with Cordelia’s help. She starts questioning her coworkers at TrendCelerate and she also questions staff in their rival competitor, CloudIndus. As Ruby conducts her investigation, Cordelia starts to learn more of her abilities that she can do as a ghost. She also starts remembering little by little of what happened on the night of her death.
Cordelia’s brother, Ian, shows up and even though she doesn't trust her brother, Ian ends up proving that people can change and be better. Ian and Ruby strike a friendship and he also tries to help her find out what happened to Cordelia.
This is yet another great book in this series and I of course recommend it to anyone who likes cozy mystery books. What I love about the series is the unique friendship between Ruby and Cordelia. I truly hope that there will be more books in this series because I feel like Ruby and Cordelia are my friends!!!
Thank you Netgalley and St. Martin’s press. All opinions are my own.
Ruby and Cordelia are back in this third book and now the mystery that they are trying to solve is Cordelia’s death. Did she really take her own life or did something else happen? Ruby decides to run her own investigation with Cordelia’s help. She starts questioning her coworkers at TrendCelerate and she also questions staff in their rival competitor, CloudIndus. As Ruby conducts her investigation, Cordelia starts to learn more of her abilities that she can do as a ghost. She also starts remembering little by little of what happened on the night of her death.
Cordelia’s brother, Ian, shows up and even though she doesn't trust her brother, Ian ends up proving that people can change and be better. Ian and Ruby strike a friendship and he also tries to help her find out what happened to Cordelia.
This is yet another great book in this series and I of course recommend it to anyone who likes cozy mystery books. What I love about the series is the unique friendship between Ruby and Cordelia. I truly hope that there will be more books in this series because I feel like Ruby and Cordelia are my friends!!!
Thank you Netgalley and St. Martin’s press. All opinions are my own.
Review of advance copy received from NetGalley
All the fun and hijinks continue onward for Ruby and Cordelia in this third mystery in series.
There's a crisis in Ruby's bathroom and she screams for help. Cordelia hesitates, not surprisingly as that is where her own body was found. Yet, Cordelia would do anything for Ruby and protect her as any she-bear would protect their own cub. Through the Kerfuffle, Cordelia has finally come to terms with being among the dearly departed. Six months in the making, she is ready to find out what happened that evening which lead to her demise. Ruby is ready to help Cordelia sort out the clues and help her friend gain some true closure.
Olivia Blacke has delivered yet another solid cozy mystery. The writing is good. The characters are well developed and certainly fun. Ruby is a sweet kid, recently out on her own. Cordelia is looking out for her; making certain that Ruby doesn't make the same mistakes she did. The action and banter is often amusing. Personally, being from Boston, I wish the mise en scène was fleshed out more descriptively. Yet fortunately, this story has all the red herrings one would hope for, and a most satisfying conclusion.
I am grateful to Minotaur Books for having provided a complimentary copy of this book through NetGalley. Their generosity, however, has not influenced this review - the words of which are mine alone.
Publisher: Minotaur Books
Publication date: October 20, 2026
Number of Pages: 368
ISBN: 978-1250336736
There's a crisis in Ruby's bathroom and she screams for help. Cordelia hesitates, not surprisingly as that is where her own body was found. Yet, Cordelia would do anything for Ruby and protect her as any she-bear would protect their own cub. Through the Kerfuffle, Cordelia has finally come to terms with being among the dearly departed. Six months in the making, she is ready to find out what happened that evening which lead to her demise. Ruby is ready to help Cordelia sort out the clues and help her friend gain some true closure.
Olivia Blacke has delivered yet another solid cozy mystery. The writing is good. The characters are well developed and certainly fun. Ruby is a sweet kid, recently out on her own. Cordelia is looking out for her; making certain that Ruby doesn't make the same mistakes she did. The action and banter is often amusing. Personally, being from Boston, I wish the mise en scène was fleshed out more descriptively. Yet fortunately, this story has all the red herrings one would hope for, and a most satisfying conclusion.
I am grateful to Minotaur Books for having provided a complimentary copy of this book through NetGalley. Their generosity, however, has not influenced this review - the words of which are mine alone.
Publisher: Minotaur Books
Publication date: October 20, 2026
Number of Pages: 368
ISBN: 978-1250336736
Review of advance copy received from NetGalley
I am having such a blast with this entire series! Finally, in this third installment, we are investigating what happened to Cordelia!
A twisty, turny murder mystery, aided by the victim herself, The Key to a Killer is a fantastic installment in the Ruby & Cordelia series. In this installment, not only do we finally unmask the big bad killer, we also learn more about Cordelia's ghost powers and why her memory has been blocking the day of the murder.
I'm really loving this series for quite a few reasons! First, I have a tendency to guess the "twists" of most mystery books within the first 20-30%, but this series actually keeps me on my toes! Second, the friendship between a ghost and a girl in her early 20s trying to figure out life is so fun to watch. Ruby is constantly trying to learn and better herself and become more of an adult, and Cordelia is learning to face the choices she made when she was alive, and using her abilities to help keep Ruby safe. Finally, I love the banter! The bits of commentary on social issues, which are few and far between, are really quite funny. Seeing a ghost from the 80s try to decipher the difference between a booty call and a butt dial? Hilarious!
Highly recommend the Ruby & Cordelia series to fans of mysteries, ghost stories, and stories of a girl simply trying to make her way in a new city! Thank you so much to Netgalley and St. Martin's Press for the chance to read the newest installment early!
A twisty, turny murder mystery, aided by the victim herself, The Key to a Killer is a fantastic installment in the Ruby & Cordelia series. In this installment, not only do we finally unmask the big bad killer, we also learn more about Cordelia's ghost powers and why her memory has been blocking the day of the murder.
I'm really loving this series for quite a few reasons! First, I have a tendency to guess the "twists" of most mystery books within the first 20-30%, but this series actually keeps me on my toes! Second, the friendship between a ghost and a girl in her early 20s trying to figure out life is so fun to watch. Ruby is constantly trying to learn and better herself and become more of an adult, and Cordelia is learning to face the choices she made when she was alive, and using her abilities to help keep Ruby safe. Finally, I love the banter! The bits of commentary on social issues, which are few and far between, are really quite funny. Seeing a ghost from the 80s try to decipher the difference between a booty call and a butt dial? Hilarious!
Highly recommend the Ruby & Cordelia series to fans of mysteries, ghost stories, and stories of a girl simply trying to make her way in a new city! Thank you so much to Netgalley and St. Martin's Press for the chance to read the newest installment early!
June 23, 2026
I received The Key to a Killer through a Goodreads giveaway sponsored by the author and publisher.
One of my favorite things about this series is the friendship between Ruby and Cordelia. On paper, having a ghost as a roommate sounds like it shouldn't work, but somehow it does, and their relationship continues to be the heart of these books.
This time around, the mystery feels especially personal as Ruby and Cordelia try to uncover the truth about what really happened to Cordelia. I enjoyed seeing the pieces slowly come together, and it was satisfying to finally get more answers about a question that has been hanging over the series from the beginning.
The mystery itself kept me guessing, but what keeps me coming back is the cast of characters. Ruby is easy to root for, and Cordelia has become more and more likable with each book. Their conversations, teamwork, and genuine care for each other add a lot of charm to the story.
This book has the cozy mystery elements I enjoy, but it also has some emotional moments that give the story a little more depth. It felt like a fitting next chapter for these characters, and I was happy to spend more time with them.
Final thought: If you enjoy cozy mysteries with memorable characters, a touch of humor, and a unique paranormal twist, this series is definitely worth checking out.
One of my favorite things about this series is the friendship between Ruby and Cordelia. On paper, having a ghost as a roommate sounds like it shouldn't work, but somehow it does, and their relationship continues to be the heart of these books.
This time around, the mystery feels especially personal as Ruby and Cordelia try to uncover the truth about what really happened to Cordelia. I enjoyed seeing the pieces slowly come together, and it was satisfying to finally get more answers about a question that has been hanging over the series from the beginning.
The mystery itself kept me guessing, but what keeps me coming back is the cast of characters. Ruby is easy to root for, and Cordelia has become more and more likable with each book. Their conversations, teamwork, and genuine care for each other add a lot of charm to the story.
This book has the cozy mystery elements I enjoy, but it also has some emotional moments that give the story a little more depth. It felt like a fitting next chapter for these characters, and I was happy to spend more time with them.
Final thought: If you enjoy cozy mysteries with memorable characters, a touch of humor, and a unique paranormal twist, this series is definitely worth checking out.
Review of advance copy received from NetGalley
I've been absolutely loving this series and have been looking forward to this book since I finished the last one and someway, somehow, this one was even BETTER.
Cordelia and Ruby are just enjoying another day together. Screaming for your ghost roommate to handle a spider and then bring up the task of solving said ghost's murder shortly after. Yup, pretty much another day for these two.
Ruby really wants to help Cordelia figure out what really happened to her and Cordelia is finally ready to do so.
I love these two. They're basically best friends at this point, least as much as a human and ghost can be. Who wouldn't a ghost bestie that can shoplift you clothes and the name brand snacks... but seriously these two have come a ling way since the first book and I love it.
Now onto the big issue. What actually happened to Cordelia....
Well they have their list of suspects. Catch Cordelia's ex in the park with another coworker. Ian, Cordelia's brother seems to actually be trying to be on the up and up. There is so much going on.
The other murders were dangerous and risk, but this one very well is the highest risk of all. But this whole book was SO WORTH IT.
I would love if this serious would continue. One of my favorites that I've come across in a long time and could read about these two solving all kinds of murders down the line.
Cordelia and Ruby are just enjoying another day together. Screaming for your ghost roommate to handle a spider and then bring up the task of solving said ghost's murder shortly after. Yup, pretty much another day for these two.
Ruby really wants to help Cordelia figure out what really happened to her and Cordelia is finally ready to do so.
I love these two. They're basically best friends at this point, least as much as a human and ghost can be. Who wouldn't a ghost bestie that can shoplift you clothes and the name brand snacks... but seriously these two have come a ling way since the first book and I love it.
Now onto the big issue. What actually happened to Cordelia....
Well they have their list of suspects. Catch Cordelia's ex in the park with another coworker. Ian, Cordelia's brother seems to actually be trying to be on the up and up. There is so much going on.
The other murders were dangerous and risk, but this one very well is the highest risk of all. But this whole book was SO WORTH IT.
I would love if this serious would continue. One of my favorites that I've come across in a long time and could read about these two solving all kinds of murders down the line.
Displaying 1 - 30 of 139 reviews