My Sister Is Going to Kill Me

by Nina Simon

From the New York Times bestselling author of the runaway hit Mother-Daughter Murder Night, a Reese’s Book Club pick, comes another fun, family-centered whodunnit about two sisters who work together to find a killer as they raft down the rapids of the Grand Canyon.

Liv and Mandy Chisolm’s yearly sister trip is a sacred tradition, an attempt to bond as their lives increasingly diverge. Liv, the ever-practical older sister, packs the color-coded itineraries. Mandy, a bedazzled human tumbleweed, brings the spontaneity.

As they set out for this year’s trip, a rafting adventure through the breathtaking depths of the Grand Canyon with a group of strangers, they hope to revitalize their relationship. But beyond the terrors of whitewater rapids, sibling squabbles, and rogue reptiles, the ferocious beauty of the river carries a darker undercurrent, and an unexpected a murderer in their midst.

When a fellow traveler is found dead and another corpse hits the water, the rafting trip flips from idyllic sister vacation to high-stakes murder investigation. Every suspect has a secret, every clue is drenched in mystery, and Liv and Mandy can hardly trust each other, let alone their own instincts. With the river raging and danger around every bend, the Chisholm sisters must work together to catch a killer—and keep their relationship from capsizing—before it’s too late.

Genres: Mystery, Thriller, Fiction, Mystery Thriller, Contemporary, Adult Fiction, Suspense

352 pages, Hardcover

Expected publication August 18, 2026

About the author

I write crime stories about strong women.

My newest novel, MY SISTER IS GOING TO KILL ME, will be released in August 2026. It is a fun, twisty mystery about two mismatched sisters who must catch a murderer as they barrel down the Grand Canyon on a whitewater rafting trip.

My first novel, MOTHER-DAUGHTER MURDER NIGHT, is a New York Times bestselling mystery about a grandma, single mom, and teenage girl who come together to solve the murder of a naturalist who washes up in the Monterey Bay.

Writing has always been my joy. In college, I was an electrical engineering student by day and a slam poet by night. After a brief stint at NASA, I started designing interactive exhibits and eventually became a museum director. I wrote two books of nonfiction about creating participatory, relevant cultural institutions.

Then, my mom got sick. I quit museum work to care for her, and I found myself turning to fiction, and mysteries, as a way to escape and find pleasure during a hard time. I wrote my first novel by my mom's side, featuring a detective/hero based on her. Now, my mom is doing better, and I'm gratefully spending my days writing, reading, and cherishing the people in my life.

I live off-the-grid in the Santa Cruz mountains. You can find out more about me at https://ninaksimon.com/

I write a very occasional newsletter at https://ninaksimon.substack.com/

Reviews

[Jenny K (on partial break) · Rating 3 out of 5]

Liv and Mandy are on their annual sisters' trip, this time, as invited guests for a new product launch, "Essence Quest." But everything starts going wrong, and when people start dying, Liv and Mandy need to figure out who the murderer is before it's too late.

I loved Nina Simon's last book and was really looking forward to this. But while it was fun, I had several problems with the premise.

The Essence Quest, and the whole worship of the company CEO, Babette, was just bizarre. Maybe I'm out of touch, but the "goddess" thing seemed very unrealistic. Ditto for the strange way she didn't seem to know who her funder was? How would that ever really happen? Or that someone so successful was getting investment advice from a down-and-out criminal when she could have hired anyone? All of these things pulled me out of what could have been a good story because they didn't make sense.

More than that, I didn't really like Liv or Mandy, who were both caricatures of their proclaimed styles; Liv was boring, and Mandy was a selfish airhead.

What saved the rating was the end. I didn't see it coming, even though looking back, the clues were all there. It was still strange, though, and unrealistic, like the rest of the book.

This is an outlier review, and I'm glad other readers are really enjoying it!

Thank you to NetGalley, William Morrow, and Nina Simon for the opportunity to review an advanced copy.

[Nina Simon]

I wrote this book to celebrate the deep, nuanced love between siblings, and to explore what happens when the pressure cooker of a family vacation smacks into a murderous plot in a remote wilderness. It's like Murder on the Orient Express if the train was a whitewater raft careening down the Colorado river, piloted by two sisters who are just as likely to throttle each other as they are to solve someone else's murder.

I had a blast researching and writing this novel, and I hope you have just as much fun reading it.

And on the off-chance it doesn't work for you, please... don't tell my sister.

[Amy Sunshine · Rating 3 out of 5]

Thank you to #WilliamMorrow and #NetGalley for the digital ARC of #MySisterIsGoingToKillMe. The opinions expressed here are entirely my own.

This was a good "keep you guessing" mystery set in the Grand Canyon. Sisters Liv and Maddie couldn't be more different from each other. Liv is sensible and grounded, an analyst for the state department. Maddie is a free spirit, always chasing her latest whim. For this years annual sisters trip, they'll be rafting down the Colorado River with a group of people as part of an "essence quest", a pre-launch for a new product from Babette's Botanique. Things go awry pretty quickly and it's clear everyone on this trip is hiding something. Liv and Maddie have to rely on each other and their different strengths to stay alive and figure out who the killer is.

This is turning out to be "sibling summer" for me and I'm enjoying it overall. This book was a fun addition to my other sibling reads.

[Jen Ryland (jenrylandreviews & yaallday)]

I am finding many of my summer mystery/suspense books hard to rate because they have such dramatic pros and cons.

The pros of My Sister is Going to Kill Me: a fun premise with two sisters who are total opposites taking a rafting trip tougher that turns into an "And Then There Were None" situation. A fantastic Grand Canyon setting. A creative means of murder.

The cons: Too many characters (I had to make a list to keep them straight) and too little time developing them to help me keep them straight. Too much time explaining a mysterious character we never actually meet (an Anita Roddick-style beautypreneur who is launching a new product). A convoluted motive.

It makes me glad I have never done star ratings because ...???????

Thanks to the publisher for providing an advance copy for review!

[Teresa · Rating 4 out of 5]

Gifted ARC on NetGalley through Crime of the Scene, @williammorrowbooks @ninaksimon
Two very different sisters, a raging river ride, nowhere to run or escape because there is a killer on this trip.
You almost feel like you are in the raft with Mandy and Liv going through that first Colorado river rapids at Horn Creek.
The messages inside the hats - are they warnings? threats? Secrets get revealed along the trip. Their dad’s history and criminal investment background comes to light which caused them to be apart for so long.
There are so many people on this trip….so many killers among them….so many dead folks along the way. I needed to keep reading just to see what was going to happen next.
These sisters are great at solving all the mysteries - especially when they work together.
Will there be a sequel?

[Jackie]

The title completely fooled me. I was expecting an immersive, tension-filled thriller, but this ended up being a very slow burn mystery that I never connected with. The plot felt overstuffed, trying to balance murder, corporate intrigue, family drama, and survival all at once. Because of that, the sister relationship, which I thought would be the heart of the story, got lost in everything else. I kept waiting for the tension to build, but it never really did. However, the two things I did enjoy were the title and the audiobook narration. Even though this one wasn’t for me, I’m grateful to HarperAudio Adult for the advance copy in exchange for my honest opinion. (Audio)

[Love_booksforlife Jen · Rating 4 out of 5]

On their annual sister's trip, opposites Mandy and Liv meet up to take a rapids and hiking trip through the Grand Canyon. But this trip has more danger than their previous ones once someone dies.

This was cool. First, I loved the setting. This made me want to go to the Grand Canyon. Simon does a great job really showing this setting. You feel the danger but also the beauty. The cast of characters are all so different but all hold so many secrets. The twist in this was really well done and laid out. I appreciated how the chapters switch back and forth between the sisters as well. They are so different from each other so you get the different perspectives on the mystery.

thank you to the author and publisher for the gifted copy!

[Elizabeth Good · Rating 5 out of 5]

Thank you to publisher William Morrow and Company/HarperCollins, NetGalley, and author Nina Simon for the advanced reading copy of this wonderful mystery set in the spectacular Grand Canyon National Park.

I loved this one. What an absolute pleasure to read!

Nina Simon's writing is engaging, eloquent, and often laugh-out-loud funny. Even when the mystery deepens and takes on a more serious tone, touches of humor remain throughout.

The Grand Canyon itself becomes one of the book's greatest strengths. Simon's descriptions are vivid and immersive, and it's obvious she's drawing on extensive firsthand experience hiking and rafting there (confirmed in the afterward). It's rare to find a mystery that so fully incorporates the breathtaking beauty of nature and the challenges of outdoor adventure. The setting isn't simply a backdrop—it becomes an essential part of the story.

A few examples which captured that for me:

The canyon walls, baked brown in the daytime by the sun’s glare, now held crystalline veins of deep red and purple. Small signs of life popped out at her: the pink, hooked spines of a barrel cactus, the white throat of a duck, a butterfly flitting serenely across the water…

———
The morning light sluiced over the North Rim, slapping the waves with brightness that alchemized the whitewater into foamy diamonds.

———

The intensity and beauty of the hike had temporarily pushed the threats aside. The sandstone ledges they traversed were narrow but navigable, and a light breeze in the paper-dry air kept her sweat at bay. Where the Colorado was a thick greenish-brown, Tapeats Creek ran fast and clear, its music less a roar than a skittering rush as it fell over rocks and lacy tendrils of moss on its way to the river.

One very delightful surprise for me was discovering that much of the story revolves around a wellness influencer company—one of my favorite things to see gently parodied. (As someone endlessly fascinated by that world, I appreciated every bit of it!) Simon has a wonderful eye for the earnestness, personalities, and absurdities of wellness culture. The satire is clever without becoming mean-spirited, and much of the humor grows naturally out of the characters and situations, making it all the more enjoyable. (Coincidentally, I was listening to a book during the time that I was also reading this one, and the parody of wellness influencer culture was so similar in tone!: Before I Forget).

Along with the mystery runs the other key thread: the relationship between sisters and the enduring bonds of family. While family dynamics, in my opinion, play a somewhat quieter role than they did in her first novel, Mother-Daughter Murder Night, they still provide an emotional foundation. Here, the mystery—and the fascinating cast assembled for the Grand Canyon adventure—takes center stage, while the sisterly connection still remains meaningful (the clever title hints at that beautifully).

I thoroughly enjoyed Mother-Daughter Murder Night -- a Reese's Book Club pick. Because I loved its local flavor and inventiveness so much, I actually expected to enjoy this one a little less. Instead, I think Simon has raised the bar. The humor especially stood out, the Grand Canyon setting is unforgettable, the writing is gorgeous, and the mystery itself is refreshingly original.

Mystery isn't my primary reading genre, so seasoned mystery readers may solve the mystery (whereas I did not!). But I suspect even readers who identify the culprit will have difficulty predicting the motivation behind the crime. I found the resolution inventive and satisfying.
This is a rare combination: an immersive outdoor adventure, sharp social satire, heartfelt family relationships, and an engaging mystery—all wrapped in wonderful prose.

Congratulations to Nina Simon on another terrific novel. It's a pleasure to support such a talented local author whose books have clearly resonated with readers far beyond our shared community. I'll happily continue following her work and eagerly await whatever she writes next.

This one will be published on August 18.

She approached Thunder Spring, letting the waterfall roar in her face and sting her hair. Close up, the water was rich with minerals, a pale aquamarine whipped into a sparkling lather. She felt an irrational desire to lick it, to gather its iridescent foam and smear it all over her body. She wondered if this was how Devon had gone from botany to Babette, out of the naked desire to bottle the glory of nature and drench herself in it.

[Just Blue Through Books · Rating 4 out of 5]

Thank you to NetGalley and to William Morrow for the ARC of My Sister is Going to Kill Me by Nina Simon.

I was really intrigued by both the adventure setting of rafting down the Grand Canyon + the description of the two opposite sisters navigating a murder mystery together. As the older, type A, Liv-esque sister myself, I greatly identified with her and her perceptions of a flighty younger sister like Mandy. The way Nina Simon wrote the sisters is one I think a lot of women are going to be able to relate to for a multitude of reasons, and their relationship and struggles and differences are truly the heart of the story here.

The story builds slowly and with lots of external and internal mystery and secrets. Liv and Mandy are two sisters in their early 30s who annually take a sister trip to try and maintain their relationship, which has struggled ever since their mom died over a decade prior. This year it's Mandy's time to select the trip location, and she picks rafting down the Grand Canyon. Unknown to Liv, Mandy has been gifted this trip for free for unknown reasons and the group of rafters aren't strangers, but all related to a beauty and lifestyle brand, Babette. As the group begins to raft down the river, Liv and Mandy must try to work together as ominous threats appear and as the star of the trip fails to join them while all the other rafters become more paranoid and suspicious of each other and their crew.

The story does build slowly, as already mentioned, and it takes a while to parse out all the individual characters and the larger backstory. I do wish Liv's actual career as a profiler had been featured a bit more prominently, but that may have interrupted the pacing -- it just seems like the type of skillset that a murder mystery would have been more reliant upon. That being said, Simon does balance Liv's skillset with Mandy's embellishments, and so the sister angle does take priority over something a bit more Sherlock-ian, which does end up working quite well in the third act. And, with their relationship and misunderstandings and love for each other being the true center of the story, these decisions do make sense and give the book its overall oomph that readers will really love.

The mystery itself had a lot of twists and turns, and Simon has herself rafted the Grand Canyon so she really vividly creates the setting, the action and the dangers. I appreciated how realistic that aspect was and how it didn't overembellish the danger, because there is enough danger on its own with nature involved. The mystery, by the end, was solvable for me before the big reveal, but it still paid off well and was worth the overall build-up of the story.

This book has definitely made me a Nina Simon fan, and I do plan to go and read her first novel as well after really enjoying this one.

[Pam Elliott · Rating 3 out of 5]

Nina Simon’s second mystery novel, My Sister is Going to Kill Me, is a whodunnit on a rafting trip into the Grand Canyon. I enjoyed Mother Daughter Murder Night and found this follow-up family crime story similarly enjoyable with a few caveats.
Liv and Mandy’s yearly sister trip is a tradition with a goal of bonding the two who could not be more different. Liv, organized and quiet, and Mandy, a risk-taker who never stops talking. Their busy lives mean that only once per year do they really get to spend quality time together. But this rafting bonding trip pushes the limits of sisterly love when a fellow traveler is found dead, and of course, nothing is more stressful than a murderer on your vacation.
The sisters work together in their sibling conflict kind of way to figure out what is going on and who is to gain from killing the head of a skin-care company and then another person connected to the same company. In fact, much to Liv’s surprise, everyone on the trip (except Liv) is related in some way to this skin-care company. It was Mandy’s turn to pick the vacation spot, and of course, Mandy has the sisters involved in a dangerous mess.
I found the rafting trip details fascinating, especially after finding out that Nina Simon inspiration for the book came from a real-life trip she took with her sister. But the characters beyond the sisters were not well flushed out and came across as stereotypical. The overt praise for the company CEO who is killed felt cultish and not realistic, while the investigation by the sisters and their interactions were sincere and true to life.
The book takes a while to get to the murder. I don’t really find skin-care products that fascinating (unlike the characters in the book) so perhaps that did not help my lack of interest in the book. Things pick up in the second half of the book; perhaps the first half should have grabbed my attention as well. Not a bad read, just not what I wanted from such an interesting concept.
My rating: 3 of 5
This ARC title was provided by Netgalley.com at no cost, and I am providing an unbiased review.
My Sister is Going to Kill Me will be published on August 11, 2026.

[Samma · Rating 4 out of 5]

My Sister is Going to Kill Me is the sophomore mystery from Nina Simon. Before starting this one, I went back and reread my review of her debut novel, Mother-Daughter Murder Night, and interestingly, I came away with many of the same feelings.

The premise of the story sounds incredibly promising, but once again I found myself struggling to connect with the characters. Liv and Mandy are sisters with completely opposite personalities, yet I still wanted more depth from both of them. When their father entered the picture, my interest in their storyline dropped even further. The supporting cast, despite being quite large, also failed to capture my attention.

The pacing was slow, with the actual "murder" not becoming a major focus until well into the story. It wasn't until about three-quarters of the way through the book that I found myself reading more quickly. Part of that may have been because I had grown tired of the cosmetics founder and her family. Their storyline felt unrealistic to me, and the almost cult-like devotion to the company founder was more strange than compelling.

The rafting scenes at the beginning were among my favorite parts of the book. Unfortunately, even those sections began to drag after a while, and I found myself skimming the descriptions to focus on the conversations taking place on the rafts.

I started piecing together the identity of the murderer around the same time the characters did, which made for a satisfying enough reveal. Nina Simon consistently comes up with intriguing plot concepts, but for some reason I continue to struggle to become invested in her characters. Without that emotional connection, the mysteries lose some of their impact for me.

Despite my criticisms, this certainly won't be the last Nina Simon book I read. Her story ideas are strong, and I'm hopeful that a future novel will provide characters with enough depth and backstory to make me fully invested in their journeys.

This was technically a 3.5-star read for me, but I rounded up.
A special thank you to NetGalley, William Morrow Publishing, and the author for providing me with an advance review copy of this ebook.

[Krista · Rating 4 out of 5]

My Sister Is Going to Kill Me follows two sister who have completely opposite personalities. Liv is the orderly type that works as a profiler for the state department, and Mandy is the outgoing type who works as a teacher and has a bad habit of being a compulsive liar. Their opposing personalities causes rifts of understanding each other. Annually, they get together for a sister vacation, and this vacation just so happens to be a hiking, camping, and rafting trip in the Grand Canyon. This trip was supposedly “gifted” to them by Mandy’s idol, Babette, who is a skincare entrepreneur and visionary. Everyone on this trip is somehow tied to Babette’s company, but not everything is as it seems as the sister’s must work together to survive their trip.

Favorite Quotes:

“Distraction is a powerful drug all its own…The real question is what we are being distracted from.”

“Most of all, she was sorry that they’d gotten to this point, with her wanting to punch her sister in the face and crawl into her sleeping bag and curl around her like a koala at exactly the same time.”

I really enjoyed this novel. I have two sisters, and there’s one that I constantly have a shaky relationship with due to our personalities and beliefs, so the two sisters in the story really resonated with me. In the end, I loved how they viewed their situation from each other’s perspective which led them to solve the mystery. I recommend this book to anyone who loves a good whodunnit murder mystery. This book is perfectly paced, and I was even surprised at the culprit reveal!

A huge thank you to William Morrow for providing this book for review consideration via NetGalley. All opinions are my own.

[Sarah Abelson Eelkema · Rating 4 out of 5]

For Fans Of: Nita Prose, Richard Osman, Kristen Perrin
Rating: 🌕🌕🌕🌕🌘
Genre: 🔪 Thriller
Violence: 🪓🪓🪓 [off-page]
Spice: 🚫
Triggers: family estrangement, snakes, near-drowning

Premise: Author of Mother-Daughter Murder Night returns with a whodunnit about 2 sisters rafting down the Grand Canyon rapids with an unknown murderer on board.

Thoughts: Looking for a book that’ll keep you up past bedtime? Search no further. Simon’s vivid, dynamic descriptions will catapult your heart into your throat & make your muscles ache like you’ve successfully navigated a category 10 rapid. Great for armchair adventurers like me, happy to vicariously raft the Grand Canyon without risking life & limb. This talent allows Simon to throw readers into the action at a sprint without sacrificing clarity of story or character development. She breathes life into her characters from their 1st intro without bogging down the narrative, especially the POV sisters, who embody the mess of family dynamics. But Simon really shows her chops on the mystery. Why were the victims murdered? How were they killed? Which of the rafters is responsible? These questions roil as the cast hurtles down the river, bounding from rapid to rapid as the most likely suspect bounces from one character to another. The sibling? The guide? The investor? The secret guest? All seem equally likely as the reader questions which clues are relevant. And even when I figured out the who, I still paddled blindly toward the why. A great thriller from beginning to end.

Thanks to Harper Collins for a gifted copy of this book in exchange for an honest review.

[Liz · Rating 3 out of 5]

My Sister is Going to Kill Me had two things going for it in my mind. I enjoyed Nina Simon’s first book, Mother Daughter Murder Night. And I’m a big fan of mysteries that take place in outdoor settings. And what’s more outdoorsy than a raft trip down the Colorado River at the Grand Canyon? The setting made it ideal for a “closed room” sort of murder mystery.
But I wasn’t entranced by the sister duo of Liv and Mandy. Mandy is the type of character that immediately grated on every one of my nerves - too immature, too oblivious and too self centered. Meanwhile, Liv seemed to have a stick stuck up her you know what. Both were just cliches of sibling polar opposites. The big emotion draw is supposed to be how these two finally learn to value how they're different and learn from each other. Yawn. The secondary characters were even less fleshed out.
From the beginning, the plot seemed to be filled with holes and unbelievable premises especially about anything to do with the business. I’m willing to put up with a certain amount of unbelievability in books I’m reading for their entertainment factor. But this went above and beyond. Scenes were so vague it was hard to envision some of them. The first murder doesn’t occur until the book is over half done, which made the first half rather slow paced. And then, it was easy to see early on who was behind the murders although I had the motive slightly wrong (probably because once again it was beyond believable).
I listened to this and Gabra Zackman did a good job as the narrator.
My thanks to Netgalley and Harper Audio Adult for an advance copy of this audiobook.

[Kim · Rating 4 out of 5]

3.75 stars
I loved the authors debut novel so was really looking forward to this one. This story focuses on sisters Liv, an intelligence officer for the state department, and Mandy, a teacher and Artist. For the last 10 years since the death of their mother they take a sister trip, alternating who plans the trip, and this year Mandy has arranged an adventure trip rafting the Colorado River in the Grand Canyon. From the beginning it is obvious that Mandy was involved in this trip for other reasons than a vacation with her sister, and we soon find out why, as we discover that all the other members of the group have a connection to a skin care cosmetics and healthcare line.

The novel is a who done it mystery, with many suspects that the sisters eventually work together to solve. I enjoyed the sister relationship, and the Grand Canyon setting and it is obvious the author was familiar with the setting with her strong sense of place. It got a bit confusing for me to keep everyone straight at times, however, and the whole cosmetic made out of a poisonous drug storyline was a little far fetched for me. If you dont think too hard though this can still be a nice mystery you can play along with and enjoy. Thank you to net galley and the publisher for this e galley, my opinions are entirely my own.

[Beth Gordon · Rating 4 out of 5]

3.75 ⭐️

After their mother’s death ten years ago, sisters Liv and Mandy committed to go on an annual sisters’ trip. Unorganized sister Mandy ropes uptight Liv into coming along on an exclusive rafting trip at the bottom of the Grand Canyon on the Colorado River, sponsored by a new wellness company CareFree. When the CEO doesn’t show and murders start to occur, the sisters must combine their strengths to solve the murders.

🩷 The Grand Canyon and Colorado River settings were described SO well. It was obvious that the author went on a trip like this, which was affirmed in the acknowledgments.
🩷 Armchair travel and adventure - loved the rafting element
🩷 The wellness company’s inner workings were well-described, if you like cutting-edge companies and business.
🩷 Propulsive plot with a well-laid mystery

⚠️ The title confuses me. The sisters were never suspects in the deaths, at least not to one another. Sure, there was a Jessica vs. Elizabeth (Sweet Valley High) dichotomy in their personalities, but their relationship was never malicious. The differences in the sisters seemed very superficial, and I often couldn’t tell their sections apart, aside from their names.
⚠️ I often like books with a business element, but this new “wellness” company CareFree that detoxifies datura for beauty uses could not keep my interest. While it wasn’t a pyramid scheme, it still had that vibe.

This is a great armchair travel novel to read during the summer while in air conditioning with a bonus mystery to solve. I thought the mystery was well-constructed, and I picked up on some of the clues along the way.

Thank you to NetGalley and William Morrow for an Advance Reader Copy. My review is completely my own.

It publishes August 18, 2026.

[Diana · Rating 2 out of 5]

My Sister is Going to Kill Me

I really enjoyed Simon’s Mother-Daughter Murder Night and when I saw her new book offered on NetGalley, I quickly requested and was happy to receive an advanced copy of the ebook. This novel is similar in some ways - as a mystery that involves family relationships along with challenging family dynamics and dysfunction. As a mystery with family dysfunction and sibling rivalries, it could have been a good book discussion choice. However, the book - the characters and the mystery/thriller fell flat for me.

There were too many key characters and character development did not provide enough background to understand them. This may have led to my confusion at times (at the beginning) to remember who was who. As to the mystery - the murder doesn’t occur until the halfway point and that’s where the story stretches into suspension of disbelief.

On the positive side, the description of the beauty and grandeur of the Grand Canyon and rafting trip were excellent and I was easily able to paint a mental picture as that part of the story unfolded. While I thought I knew who was responsible for the mysterious messages and resulting murders, there was an unexpected twist.

Thank you Nina Simon, NetGalley, and William Morrow for an advanced copy of the e-book.

[Andria Lambert · Rating 4 out of 5]

This is the first book that I have read by this author, though I did purchase Mother-Daughter Murder Night and it's on my tbr list.

In My Sister Is Going to Kill Me, there are sisters Mandy and Liv, two sisters that are very different from one another, they are polar opposites but still want to have a sister relationship and so they plan a yearly trip together. They plan an annual trip to go rafting this time, its Mandy's turn to select the location and she chooses that they go rafting on the river through the Grand Canyon. There are a host of fellow travelers on this trip and then there are deaths. Now, there are a host of suspects to consider as a potential killer. The sisters must somehow work together to figure out who the true villain is and survive this trip. I thought it was a good little mystery with the amateur sleuth vibes going on. Maybe not a 5 star read but an entertaining solid read. I was kept entertained and like the rafting and outdoorsy settings, I myself had a wilderness outdoorsy vacation this year where anything can happen and everything's a risk, and really love those survival type vibes. I am very interested in reading the one book that's on my tbr list and any future books by the author.

Thank you Netgalley and William Morrow for the complimentary copy of the story.

[Jennifer · Rating 4 out of 5]

This was one of those books I picked up and didn’t really put down.
The story follows two sisters with a complicated, strained relationship, and that tension is there from the very beginning. What stood out to me most is how real that relationship felt. It wasn’t overly dramatic or forced—it was the kind of strained dynamic that builds over time, with history, resentment, and things left unsaid. At times, it felt a little too relatable, especially in the way family relationships can be messy, layered, and not easily fixed.
I found myself constantly questioning who to trust and what really happened between them. Just when I thought I had it figured out, something would shift. It’s very much driven by that psychological tension rather than shock value.
The pacing is quick, the chapters are short, and it’s easy to move through. It’s more about the unraveling of the relationship and the truth than anything overly graphic, which I appreciated.
There were a few moments where I wanted a little more depth, especially with some of the reveals, but overall it kept me engaged the entire time.
Rating: 4 stars
If you like character-driven thrillers that lean into complicated, realistic family dynamics, this one is definitely worth picking up.

[RMazin · Rating 4 out of 5]

Yes and no for me -rounding up to a 4 from 3.5 stars. The best parts were the Colorado River journey through the Grand Canyon and how all the travelers cope with the environment. The focus is on two very different sisters who have chosen unique ways of coping with the world around them. Liv is the analytical one who needs all the facts before proceeding. She is data driven so out of her element here with few resources to rely upon. It gets deadly when a fellow traveler’s body is found. Mandy is the emotional one, always ready to embellish if an exaggeration or even a lie will elicit more info in this mystery. The clash of approaches and their history put the sisters at odds which they must surmount to keep each other from harm’s way. Moreover, the trip is sponsored by a trendy wellness company, think GOOP on steroids, as a wilderness adventure product line reveal. The wellness company includes prickly personalities and suspects. Even the river cruise guides may be implicated. Got a bit lost in some of the wellness company objectives but did enjoy the whitewater rafting. Recommended as a beach read. Thanks to Netgalley and the publisher for providing this title, which is misleading!

[Alissa · Rating 3 out of 5]

I enjoyed this breezy whodunnit. Although I read it in print, there are a few things about it that would make it good as an audiobook - there are only about a dozen characters to keep straight and most of the chapters are propulsive, which for me is always a better listen than meditative prose.

This book is light reading. Think summer vacation reading. The characters are mostly different stereotypes and don’t get any more nuanced. While there is a little bit of a deeper message about the sisters discovering each other’s strengths, it’s really more of a romp. I had fun with it and think if you enjoy plot-focused mysteries and thrillers you will too.

The one thing I struggled with was that we hear over and over that Mandy is a liar, see her lie, and are still expected to like her as a protagonist, and even grow to consider it a strength. This part didn’t really work for me and I thought it made Mandy unlikable, when she was otherwise a fun character. It was a lot easier to understand and root for Liv.

Overall, a good summer read when you are looking for a an easy read in an outdoorsy setting that moves along at a brisk pace.

Thank you to William Morrow, Netgalley, and the author for the ARC.

[Jennifer Smith · Rating 4 out of 5]

This was such a fun vacation read! I love books about sisters as well as destination thrillers, so this set-up was right up my alley.

Liv and Mandy are opposites in *every* way, and when their annual sisterly bonding trip goes awry (bodies start dropping!) they must navigate a high stakes closed-setting pressure cooker situation while also working through their own sibling issues. I loved their relatable sisterly banter as well as the way their differing personalities helped them work together to survive and solve the whodunnit plotline. The other attendees on the trip include another set of siblings who co-run a hugely profitable wellness cosmetic brand, so it was fun to watch those power dynamics unfold under pressure as well.

I gobbled up the humorous lighthearted tone, while taking a fast-paced whitewater adventure through the scenic Grand Canyon. It was such a vivid setting the author has clearly researched (and loved) themselves.

If you are searching for a propulsive, fast-paced, cozy-adjacent mystery that blends murder with some family drama, you should pick this upcoming release up!

[Jeff · Rating 3 out of 5]

Liv and Mandy are taking their annual “sisters” trip rafting at the Grand Canyon, part of a group of strangers. But the rapids aren’t the only danger on this trip when one of the group is found dead. My Sister Is Going To Kill Me is basically a whodunnit, with the two sisters doggedly trying to find the murderer. The story takes a while to get going, and we learn that this trip is actually a product launch for a revolutionary skincare brand, and the group is all connected to the company. There are a lot of characters to keep track of, and the plot gets unnecessarily complicated with the inner workings of the skincare product at the forefront. I thought the story didn’t really sync with the book jacket blurb, so this was a disappointment. Not a terrible read, just less than what I was expecting. I received an ARC of this book from the publisher through NetGalley in exchange for an honest review.

[Anna J · Rating 3 out of 5]

Liv and Mandy plan a yearly sister trip. This year was Mandy’s turn to pick the trip and she has planned a Grand Canyon raft trip. I got a kick out of the two sisters as they are polar opposites of each other. Liv is the strait laced, planner, organized and on time. Mandy is a free wheeling, looking for a good time, lies to get free things and get what she wants and flies by the seat of her pants. These two bicker along the way but beneath that they have a strong bond.

This trip was all part of Essence Quest put on by Babette to show off her new care free line. Each person on the trip. It was a bit bizarre how everyone seemed to worship Babette so when she doesn’t appear in the beginning as planned Liv is suspicious. The leaders insist she will show up and push to start the trip. Each person on the trip is a suspect and it’s up to Mandy and Liv to figure out who did it.

I liked how this had many layers and not everyone is who they claim to be keeping you guessing until the end.

[Liz · Rating 4 out of 5]

Nina Simon returns with more strong female characters facing mystery and challenge in "My Sister Is Going to Kill Me". I loved "Mother-Daughter Murder Night" and enjoyed this one as well! Liv and Mandy set out on a sister trip together rafting down the Colorado, but murder and mayhem ensue. Their opposite personality traits clash as their group deals with the mystery of a murdered skincare CEO. One sister uses her investigatory skills and the other uses the power of being a people person and stretching the truth a little to get what she needs, and despite their sketchy dad appearing too, they eventually get to the bottom of the two murders that happen on their trip. I almost felt a bit bogged down by the canyon and river descriptions, like they were distracting from the story, but having rafted out west before this brought lots of memories back! I hate the kitchy skincare business stuff, but I think the point was for Babette to be over the top. I wish we got a little more of the supernatural-esque nature of the datura plant and I wish Katy the rafting guide had more screen time, I liked her! This is a fun twisty read with beautiful grand canyon visuals and I'd definitely recommend it. Thanks to the publisher for the ARC, I'm grateful to get to advance read Nina Simon again!

[jo ୨୧ · Rating 4 out of 5]

thanks to netgalley and the publisher for an advanced copy in exchange for an honest review. all thoughts are my own.

you know what, yeah, this was a solid thriller, i do think i liked simon's debut novel better (the humor and vibes of that just hit for some reason, esp with the mom and grandma relationship).

i do think that the sister relationship was so cute and wholesome to read about but i also don't have a sister (only children rise up) so that just didn't hit for me.

however, i absolutely binged this novel in a night and i think it is the legit perfect novel for the summertime.

i did peg a lot of the plot but that's genuinely just my problem actually, im just too smart--okay i'll wrap it up. anyways, this is such a fun cozy thriller and i rec this for a beach vacation (bonus points for the setting of this book!)

[Erica Winchester · Rating 3 out of 5]

Thank you to NetGalley for the opportunity to read this ARC.

The premise of My Sister Is Going to Kill Me immediately drew me in, and I was excited to dive into a story on the complexities of sisterhood. While this novel ultimately wasn’t the best fit for my personal reading preferences, I can certainly appreciate what the author set out to accomplish.

The relationship dynamic between Mandy and Liv felt authentic, capturing the love, frustration, history, and tension that can exist between siblings. I especially found Mandy to be a relatable character at times, which helped ground the story emotionally.

Although the story didn’t unfold in the way I had anticipated based on the synopsis, reading is such a subjective experience, and this one simply wasn’t the right match for my tastes. I appreciate the opportunity to read it early.

[Sarah · Rating 3 out of 5]

Thank you to NetGalley and HarperAudio Adult for a free advance copy audiobook (written by Nina Simon and narrated by Gabra Zackman) in exchange for an honest review ❤️

Sisters Mandy and Liv are opposite as can be. Every year they take a vacation together, but this year's trip rafting in the Grand Canyon turns deadly. Part of me kept thinking this was going to turn into a fast paced thriller, but this is much more of a slow burn mystery. There is a focus on sister dynamics, corporate greed, and ultimately surviving until the murder can be solved.

The audio narration was great. For a wide cast of characters in the rafting group, the voice acting made it easy enough to keep everyone straight.

Overall, I give the story a solid 3 stars ⭐ ⭐ ⭐. While it didn't rank at the top of my list, it was still a solid read and I think it has great potential for more stars from the right readers!

[ANGELA L. · Rating 4 out of 5]

Thank you to NetGalley and William Morrow Publishing for providing me with an ARC!

I really enjoyed the setting of this thriller, and I found the relationship between the two sisters to be authentic and relatable. Their annual sisters' trip quickly takes a dark turn, and before long, everyone involved becomes a suspect.

The mystery kept me engaged as the tension steadily built, and I found myself questioning every character's motives. With its compelling premise, engaging characters, and well-paced suspense, this was an entertaining thriller from start to finish.

Overall, this was a great, quick summer read that I thoroughly enjoyed and would recommend to fans of twisty psychological thrillers.

[Lisa · Rating 2 out of 5]

I’m sorry I didn’t like this book better, because I enjoyed the author's first book, and she lives in my area. But this one was kind of a mess. Mandy and Liv are going on their annual sisters’ trip, this time white water rafting in the Grand Canyon. From the beginning, there was something suspicious about all the guests and their relationships with each other. They all turned out to be invited guests for the product launch of a new skin care line. For me, there were too many characters to keep track of and too much information about influencers and skin care. I skimmed ahead to find out who died, then jumped to the end to find out who’d done it. Thank-you to NetGalley, William Morrow, and Nina Simon for the ARC of this title.