Sub-Rosa

by Charlotte Mills

A gripping British lesbian murder mystery that asks what price we are prepared to pay to find out the truth.

Outcast Ashley Spencer is in her second career as a rookie police constable in Cambridgeshire when she is rammed off the road one terrifying night.

Forced to rescue her is undercover detective Darren “Mac” Mackenna, who claims to be a passing carpenter. A lifelong loner, Mac is leery of all relationships, and has been preoccupied with finding out how a close friend and colleague died.

Impressed and grateful, Ashley uses her skills to track down her anonymous hero. An unlikely friendship forms between the opposite women.

Still, Mac is suspicious: Can Ashley be trusted, or is she really part of a corrupt network of cops Mac is trying to expose? Should she trust her head or her heart to find the truth?

Genres: Crime, Lesbian, Thriller, Mystery

270 pages, ebook

Published June 4, 2025

About the author

I guess I would describe myself as a southerner even though I have lived in the north of England for some years now, I work hard to keep my accent intact. After having several careers in the arts, conservation and education where writing or using my imagination has always been in the background I finally took the plunge with self publishing in 2014.

In 2017 I was awarded a Gold Medal for the Fiction - Gay/Lesbian/LGBT category in the Global Ebook Awards for my double novel Out of The Blue - Latent memories.

My first book to be published with Ylva in 2019 was Payback, it was made a finalist in the 2019 Lesfic Bard Awards.

My latest book - Sub-Rosa is set in the south of England and revolves around corruption in a small town and an undercover police officer desperate to find the truth.

Reviews

[Diane (IF U'RE PRIVATE, PLEASE SKIP ME!!!) Wallace · Rating 3 out of 5]

**'Always remember that the structure and premise are sometimes the keys to telling your narrative..'

Okay read!
A somewhat good detective mystery but meh on the romantic relation between the protagonists -- never felt like they had any chemistry...

[Sandra · Rating 5 out of 5]

4.5⭐️
I couldn't resist a murder mystery story by Charlotte Mills.

Undercover agent Darren Mackenna “Mac” of the National Crime Agency is between assignments when she learns that her former mentor has died. Suspicious about the circumstances, she begins to investigate undercover. In the process, her path crosses that of Ashley Spencer, the “new girl” at the Cambridgeshire police station. Ash wants to use her photographic memory for something more important than teaching children as a teacher. But shortly after she starts, she is rudely pushed off the road, and it drives her crazy that she doesn't know why and who saved her life.

The whole plot surrounding the police station, Ash's work, her dealing with her so-called colleagues, and Mac's undercover work is exciting, even if it was relatively clear, at least in part, who the villains were. I love detective work; snooping around and piecing together the pieces found to form a complete picture is always interesting, fascinating, and exciting.

The two women hit it off right from their first encounter, and a friendship with the potential for more quickly develops. However, the fact that Mac has to hide her true identity and therefore cannot always tell the truth quickly becomes a burden on the relationship, leading to misunderstandings and mistrust. But the attraction between them is strong. Their knowledge of human nature and their intuition help them find their way to each other.

I liked both women from the start; they have strong personalities but are not superwomen, they have their hearts in the right place, and they want to make the world a better place. I loved their banter, and their conversations were entertaining and good.

Thank you to Ylva and NetGalley for providing an ARC for an honest review.

[currentlyreadingbynat · Rating 4 out of 5]

Sub-Rosa was a book I’d been looking forward to — I’ve loved Charlotte Mills’ Payback series, so I was excited to dive into something new. And while I did enjoy this, especially the premise and the dynamic between Mac and Ash, it didn’t quite hit the same high notes for me as her previous titles.

There’s a lot to like: an undercover NCA agent chasing down the truth behind a mentor’s suspicious death, a rookie cop trying to stay afloat in a hostile workplace, and the slow burn of a romance complicated by secrets and identity. The chemistry is there, and I really liked both characters individually. But at times I found the plot a bit hard to follow, with characters and events feeling slightly muddled — I had to flip back a few times to reorient myself. The blurb also made me expect a slightly different type of story, which may have shaped my expectations unfairly.

Still, I was invested enough to keep reading, and there were some great action scenes and emotional beats that landed well. I’ll definitely keep reading anything Charlotte Mills writes.

Many thanks to Netgalley and Ylva Publishing for a copy of this novel. ARC provided in exchange for an honest review.

[Cherie · Rating 5 out of 5]

This was a detective story about DCI Darren Mackenzie who’s mentor Doogie has died from apparent suicide. Mac goes undercover to find out the truth. Ashley Spencer is a new police officer, she has an ability to recall any person‘s face. So she quits teaching and switches over to law enforcement to make a difference. Ash is transferred to a small town English village where Doogie had been working. During her patrol she meets Mac and they have an instant liking for each other. Mac keeps her role as a detective secret from Ashley and I liked the awkward situations that took place in keeping the secret.

I enjoyed the detective work to solve the mystery and catch the bad guys. Both characters are well developed and the dialogue between them was fun.

It’s been awhile since I’ve read a Charlotte Mills book and I enjoyed this one.

Thanks to Ylva Publishing and Net Galley for the opportunity to read and review this ARC.

[JulesGP · Rating 4 out of 5]

I really enjoyed this author’s Payback books so I was looking forward to Sub-Rosa. Mac is an undercover agent for the National Crime Agency (NCA) which is sort of the UK equivalent of the FBI/DEA agencies in the usa. She has just completed her latest assignment and gets the terrible news that her mentor, Dougie, was found dead. She decides to look into his death, not believing that it was a suicide. Ash is a rookie police officer when she first bumps into Mac who at that point is posing as a construction worker while she continues her investigation. They become friends and more.

My favorite parts of the story are when Mac is in action, confronting bad guys or when she is snooping around. But much of the book is focused on the romance between Ash and Mac which slows down the suspense aspect but you kind of know what’s going to happen anyway so it’s all good. The spice is hot. There are some misconceptions because Ash is not aware of Mac’s true identity and that’s a favorite trope of mine. Always love the reveal.

Ash is a secondary school teacher turned police officer. A 30ish rookie who is very much alone in an extremely corrupt police station where she is the only woman. When Ash is around these other officers, the danger ratchets up. I wish there were more Ash police scenes because the tension is so good when she is on the street patrolling alone or going toe to toe with the jerks at work.

Overall, a solid romance with plenty of heat and a mystery lite. 4.25 stars.

Thank you to Netgalley and the publisher for the arc. I am leaving a review voluntarily.

[Lisa · Rating 4 out of 5]

If you like sapphic detective stories this one is pretty solid. Both Mac and Ash are likeable characters, good storyline and a little spice.

[mtrics · Rating 5 out of 5]

I received an ARC in exchange for an honest review.

Sub-Rosa is an engrossing whodunnit mystery that follows two women: one going rogue to clear her old mentor’s name and find his murderer, the other trying to survive in her new toxic work environment.

While the story can be predictable at times, Sub-Rosa can't be accused of taking itself too seriously. It embraces a campy approach to crime-solving by, for example, having a main character drop a pen at just the right moment to be out of sight, conveniently overhearing the villains being villainous without being noticed. The book is a treat right from the opening chapters, even before the major events teased in the marketing/synopsis of the book take place.

My only real complaint, if you can call it that, is that the POV changes can be a bit jarring. It’s written in third-person limited (thankfully!), but sometimes the only indication of a switch in perspective is a small decorative break between paragraphs.

Overall, I found the book charming and unpretentious. It’s fun, a bit cheeky, and features strong characters with a solid mystery at its core. The balance between romance and crime-solving shenanigans is just right, and the chemistry between the leads feels both tangible and believable. I really enjoyed this and would recommend it to anyone looking for a classic procedural cop novel with an amazing lesbian relationship at its heart!

[Fran Sappharc · Rating 3 out of 5]

Good start, lots of questions….. my main one being the female lead the name.….. Actually I have lots of questions and I look forward to it all unfolding. It unfolded a wee bit slowly, both the relationship and criminal behaviour. Tension in either romance or rum goings on was lacking. I still want to find out what’s going on but to be honest, wish they would get on with it. When the mains “get together”, they get together several times. Unfortunately I just wanted them to get on with getting on top of the bad guys rather than each other.
I found the ending tense, full of taut writing, so happy to up to a 3, aided by the final 10%.

[Misha · Rating 4 out of 5]

(rounded down from 4.25)

This was a really interesting and down-to-earth police investigation book. The mystery isn't really mysterious, but Mac carefully navigating her investigation into potentially dirty cops is really engaging. PC Ashley Spencer's late start in a career as a policewoman after being a teacher is also a really cool backstory, and I enjoy seeing her and Mac develop their relationship while in the middle of fairly dangerous circumstances.

[Celina · Rating 3 out of 5]

Part of it felt like this book was connected to another book like a series but I haven't read it. I haven't seen any other book connected.

[Carol Hutchinson · Rating 5 out of 5]

Gripping mystery with unexpected twists!

Mac is the anonymous person who comes to Ash’s rescue when she is rammed off the road, and Ash just has to track her down. They form a friendship that leads to Mac finding out who Ashley is, but she is then wary she might have something to do with the corrupt cops she is trying to expose in connection with the death of a close friend.

This was so good! The undercover element kept the forming relationship between Ash and Mac intense. I also loved that this is set in the county I live in, so even more exciting for that personal connection. It was easy to empthaise with Mac right away because the death she was looking into was personal and held a lot of meaning to her, therefore her determination was fuelled on emotion. What I loved about Mac was that even during a time when she was investigating and undercover, she didn’t hesitate to help someone in need, even when she was aware of who they were and how it could jeopardise her position. Even when Ash found her, it would have been easy to try and get rid of her but she didn’t. If anything she got more involved and further put herself in potential danger.

Ash had a curious spirit that I adored. It was just in her nature to want to know why Mac had been there to help her in her moment of need and who she was. Typically she also kept her wits about her when it came to Mac and there was definitely drama as a result when she discovered who Mac really was. At that point she’d mostly ruled out Mac not being who she thought she was, but that’s the problem with undercover operations and getting too close to someone not factored in. It made for a great twist on the story and a later tension that left me wondering if Ash would help Mac out or not.

Really gripping mystery that was exciting from the start and kept me hooked until the very end.

[Sue Plant · Rating 4 out of 5]

would like to thank netgalley and the publisher for letting me read this book

when an underground cop comes out from her latest job to find out her mentor had committed suicide she nearly loses it

but then she starts using her brain and things dont add up.... so when the email from him arrives at first she is stumped but its coded and as soon as she unlocks the code she knows that something is very very wrong

and so she begins investigating not really knowing who to trust....

well i have to say i am thoroughly impressed with how this storyline played out.... the plethora of characters so confusing at times but they all made sense in the end.... good ending

[3DKing · Rating 3 out of 5]

The pacing didn't work for me. The romance begins around ~50% and the murder-mystery gets wrapped pretty fast without any more input from the MC. For such a long investigation to resolve everthing in 5-10% of a dramatic third act feels a little undeserving.

[Elsa · Rating 5 out of 5]

4.5 stars

[SSA · Rating 2 out of 5]

I didn’t like this story. The mystery was underwhelming and the characters weren’t all that interesting to follow.

This book was really boring and barely anything happened for 70% until everything was revealed and quickly resolved. I mean the rescue mentioned in the blurb happened at the 40% mark. Very little investigating occurred on page. And then because of a really dumb move by the guys, everything came out and they were conveniently defeated.

I also didn’t really believe in the relationship between Ash and Mac. Their romance was lacking in chemistry to me.

[Sam]

I’ve read other books by Charlotte Mills and especially Payback is one that stuck with me for excellent writing and unexpected plot twists. I think this story might be the opposite of that one for me. I found the story to be a bit lacking, I never really felt the tension and suspense I think was needed for this story.
The mystery/ police story is solved too easily, the romance is too easy as well. Even the “dark moment” wasn’t dark or dramatic.

While I wouldn’t say this is a bad story, it isn’t, it isn’t what I was hoping for with Payback in the back of my mind. I just had too high, too different expectations of what this story was going to be.

[M the avid reader · Rating 4 out of 5]

Less creepy than her other books (3.5 stars)
I've read two other books by Charlotte Mills, both of which had creepy villains and unnerving happenings in the storyline. So before reading Sub-Rosa I prepared myself, assuming it would be in the same vein as the others; turns out that wasn't necessary. It has some horrible and unlikable (on purpose) secondary characters and when the tension ramps up your reading speed may increase proportionally to see what happens next, but there's plenty of humor to go with the romance blooming amidst intrigue, mystery and suspense. Main characters Mac and Ash have an original first meeting that complicates things when they cross paths later on thanks to the circumstances of that first encounter and Ash's unique and rare 'superpower' (for lack of a better word); the push pull in their relationship kept me wondering how they'd sort things out with as little angst as possible. I was rooting for them early on despite everything being thrown their way and got attached to them, wanting no harm to come to them.
There were twists in the storyline I saw coming and at least one that felt like a curveball I didn't see coming although the clues may have been there and I missed them while reading. My focus was more on the romance developing than the mystery aspect of the story until the suspense kicked up several notches. In addition to the unlikable secondary characters, some of whom I'd mix up in my mind when they weren't mentioned for a while, there were some more appealing ones including an adorable dog who needed more time on the page. A note for non UK readers: some acronyms used in the story are UK specific but there aren't many of them.
If you're in the mood for a low key mystery intrigue suspense story with lots of humor, despite the darker elements in it, and a romance that is both sweet and heat, give this one a go. And check out the author's other books if you like being weirded out by twisted baddies. I look forward to reading whatever she publishes next.

[Tiffany · Rating 4 out of 5]

3.5/5 rounded up.

I usually start with a quote and then pepper those in throughout my review, but for once, I don’t have one. There just… weren’t any profound, gut-puncher lines. That left me feeling bereft.
Let’s start with what I like: the plot and the mystery. Well done! I thoroughly enjoyed the storyline; it was very gripping! I was absolutely hooked from start to end and I couldn’t wait to figure out what happened. That part was 5/5.

The romance… well, I came for the romance but it was severely lacking. I cared about the women individually but I wasn’t at all convinced of them together. Seemed forced and unrealistic. Or perhaps not enough was written to make it believable or convincing. Luckily, I quickly stopped caring about how disappointed I was by the romance because the mystery was so interesting and gripping.

I have to say, in retrospect, the summary (though everything mentioned in it did happen) didn’t quite match with what I read. Mac didn’t spend that long being suspicious of Ash (in fact I’d say Ash was suspicious of Mac for longer), and the ramming-off-the-road event wasn’t as central as the blurb would suggest. Just a thought.

My main gripe with this book is… GOD, THE GRAMMAR AND OTHER MISTAKES! There were so many, and I could attribute some of it to Britspeak, I would know, I live here now, but… “Mac picked up her phone and opened the camera app zooming in she focused it on the two addresses”, and an instance of “rreplied,aware” (double r, no space) as well as Riley Walters being referred to once as “Waters”… Every instance took me away from the book as I reread the words, unable to believe what I was seeing.

All that said, the plot and the mystery were great so I would still call this an enjoyable read.

[Kaye · Rating 4 out of 5]

(3.5 Stars) I am usually a fan of police procedural novels and gave the author five stars on the last book I read from her. Detective Inspector Darren (Mac) Mackenna comes off a longtime undercover assignment to learn that an old friend and mentor has died. She is shocked to learn it was suicide and decides to investigate further. When she finds some clues intentionally left by him she knows she is on the right track. Ashley Spencer is starting a new career as a new constable in Cambridgeshire. She was previously a school teacher. Things don’t seem to be quite right at her precinct. When Ashley’s car is forced off the road and calls for help she is rescued by Mac.

For me the favorite parts of the story were Mac and Ash. Often in detective stories a romantic encounter is thrown in at the end. But here it is very much part of the story. Mac isn’t sure how much she can trust Ash as she works with the same officers that covered up her mentor's death. The police part of the story was lacking for me. There was a lot of checking CCTV and background checks. But it wasn’t like Mac went undercover on the police force. She is posing as a building construction manager. I am going to round up because of the romance but I wanted more from an investigative side. Thank you to NetGalley and Ulva Publishing for the eARC and I am leaving an honest review.

[Henriette · Rating 4 out of 5]

Very British police procedural
Yes, you caught me red-handed: I am a sucker for a good, British police procedural - and Charlotte Mills delivers (again) in spades. My satisfied hum started with the first line: „Detective Inspector Darren MacKenna“ - I love those titles! DI, DCI, PC - put the kettle on, bring the biscuits and lets see what this story is about.
We get DI MacKenna (in short: Mac) who just returns from an undercover assignment. She finds out about the death of her police mentor and becomes instantly suspicious. Off she goes in her down time, undercover, to investigate further. PC Ash Spencer is a rookie, still working very much by the book, thrown into deep waters at her first station. Their paths collide. Both women are not sure where they stand in the investigation, but there is a budding attraction between the two women.
There is plenty of going-ons and a good mystery that needs to be solved. The story unfolds slowly, methodically - with a good, detailed setting. Mac and Ash are no-nonsense and competent with enough background to relate. The pace takes up considerably at the end. Very satisfying.

I received an ARC via netgalley. The review is left voluntarily.

[Rosi · Rating 3 out of 5]

This police plot offered little to no surprise; in fact, it was quite predictable. What somewhat redeems the story is the likability of both protagonists. Mac is a police officer who typically works undercover, leading to an unstable personal life. However, the death of a friend makes her suspect something shady is afoot. In her investigation, she crosses paths with Ash, a rookie police officer who, unbeknownst to her, has stumbled into a police station rife with corruption.

Ash is caught in the middle of everything, completely unaware that even Mac isn't being entirely truthful. However, Mac doesn't know whom to trust and, as a result, is hesitant to involve Ash in her suspicions, which concern members of the police station where Ash works. The plot becomes complicated but isn't overly mysterious; there's a final surprise that, while not far-fetched, feels somewhat rushed in the epilogue. While not a bad read, there are much better-developed stories within this genre.


Ylva Publishing was kind enough to send me a copy via Netgalley for an honest review

[Shannon Luchies · Rating 4 out of 5]

Undercover officer D. Mackenna has just finished a case to find out a old friend and cop, Dougie Parks, is dead by suicide. She smells a rat, as it's wildly out of character.

PC Ash Spencer has just been assigned to the unit, and something clearly smells. And even a surface look shows the unit is corrupt as heck. The only good news is her running into Mac, a (apparent) civilian who's very cute.

Mac doesn't trust Ash as she was at a station Dougie was investigating, and Ash isn't sure of Mac as she appears to be sneaking around for unknown reasons.

Ash us upset once she finds out what Mac is really doing, but they join forces in the investigation.

(I do kinda go 'huh' at Mac apparently having no one in the police force that she trusts to look into this.)

4 stars out of 5. Solidly good read.

[Jamie R. · Rating 4 out of 5]

This was a thrilling ride. Undercover detective, Mac, hears of her mentor’s suicide. She suspects foul play and takes personal time to investigate. She has a trusted crew to assist her, but is unsure who she can trust in the police department. Ash is a new officer, paying her dues as a female officer in an unfriendly department.

Ash the investigation continues and takes Mac down various trails to the truth their cautious friendship grows. Unbeknownst to Ash, Mac is the mysterious woman that saved her life after her car crash.

The story is intriguing and suspenseful and I easily like both of the MC’s. A good story that flows well.

I received an arc from NetGalley and Ylva Publishing in exchange for an honest review.

[TheLisaD · Rating 4 out of 5]

In Sub-Rosa, Charlotte Mills crafts a suspenseful and emotionally charged narrative centered on betrayal, danger, and the pursuit of truth. As protagonist Ashley delves deeper into a gripping mystery, the stakes escalate—not only for the secrets she’s determined to uncover but for her own survival. Mills balances tension with intimacy, exploring a complex relationship that adds depth to the unfolding drama. The connection between the characters is compelling, though certain revelations challenge the boundaries of trust and forgiveness. With its sharp twists and emotional resonance, Sub-Rosa is a captivating exploration of loyalty tested under fire.

[Victoria · Rating 4 out of 5]

I’ve read Charlotte Mills’s Payback series and really enjoyed it, so I was excited to pick up this book. I’ll admit, it took me a few more chapters than usual to really get into it, but once I did, I couldn’t put it down. Mills has a way of slowly peeling back her characters and their secrets that keeps you turning the pages. That said, the blurb gave me a slightly different impression from the actual story. Overall, it turned out to be an engaging and emotional read that I’m glad I didn’t give up on.

Thanks to Netgalley and Ylva Publishing for a copy of this novel. ARC provided in exchange for an honest review.

[Shannon bagnall · Rating 4 out of 5]

I’ll start with what I didn’t like as it’s only one thing, the sex scenes it was kind of like it was forgotten and wrote in afterwards.

I really enjoyed the plot and the little bits of information like about Mac’s mum and dad and their stories, it made the book flow nicely. I also enjoyed how you were kept guessing until the end, I did guess some of it but not the full thing.

Overall an enjoyable read

*full disclosure I was given this book in exchange for an honest review through NetGalley*

[Andrea · Rating 1 out of 5]

This story was lacking all around for me. The mystery was stilted and not much investigating actually happened. Instead all the facts just came to light ezpz and there wasn't much of a mystery at all. Mac and Ash did not have any chemistry to me so the romance aspect of this book fell short. If you are looking for a solid lesbian detective mystery, seek out some other authors like Catherine Maiorisi or Eve Zaremba. This book also needed another round of editing, silly mistakes like labelling Stringer as Springer.

[MiskaCZ · Rating 5 out of 5]

I received an advance review copy for free, and I am leaving this review voluntarily.

This is another book from the author and I really enjoy the reading. It is a good crime story with experienced detective Darren “Mac” Mackenna, who works mostly undercover and a newbie constable Ashley Spencer. Darren try to find the true about the death of the colleague and Ashley help on the way. The story has good twists.

[Susan Ferrante · Rating 5 out of 5]

A Great Mystery and Slow Burn Romance

A police detective is dead and the ruling is suicide. A good friend suspects it was murder. This story is well developed and kept me reading into the late hours. I look forward to more books by Charlotte Mills.

[Grace · Rating 4 out of 5]

3,5

didn’t connect with the characters very well with made this a hard read