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Undercover Madam
She was supposed to catch the criminal. . . not fall in love with her.
All Charlotte Castro ever wanted was to be an FBI agent. When her best friend, a Miami detective, presents her with an opportunity to go undercover and bust a madam to the rich and powerful, Charlotte’s dreams are finally within reach. All she has to do is get an accounting job at Alexandra Leon’s spa and collect evidence that will bring her to justice. If she can do that, the police chief will pull strings to get her to Quantico.
There’s only one complication. Charlotte didn’t count on the uncontrollable chemistry between her and Alexandra.
When Alexandra met Charlotte, a fiery woman nearly half her age, she didn’t expect to be so drawn to her. When passion transforms into something deeper, Alexandra wonders whether she can trust the eager Charlotte with her secrets. Could she be the true partner Alex has been waiting for?
In this swelteringly steamy, age-gap, lesbian romance, two women risk their freedom for a chance at love.
All Charlotte Castro ever wanted was to be an FBI agent. When her best friend, a Miami detective, presents her with an opportunity to go undercover and bust a madam to the rich and powerful, Charlotte’s dreams are finally within reach. All she has to do is get an accounting job at Alexandra Leon’s spa and collect evidence that will bring her to justice. If she can do that, the police chief will pull strings to get her to Quantico.
There’s only one complication. Charlotte didn’t count on the uncontrollable chemistry between her and Alexandra.
When Alexandra met Charlotte, a fiery woman nearly half her age, she didn’t expect to be so drawn to her. When passion transforms into something deeper, Alexandra wonders whether she can trust the eager Charlotte with her secrets. Could she be the true partner Alex has been waiting for?
In this swelteringly steamy, age-gap, lesbian romance, two women risk their freedom for a chance at love.
318 pages, Kindle Edition
First published July 4, 2021
About the author
J.J. Arias
38 books1,589 followersHello! And thank you for finding me!
I am an independent author writing about fictional lesbians of all varieties.
My writing journey began with fan faction, and as much as I LOVED being part of a community of super fans, I got tired of working with other people’s characters to tell my stories. I started asking myself: Why should we string together pieces of subtext when our community deserves well-developed main-text about LBGT people and those who love them! So, that is what I aim to deliver.
If you want to know a little more about me personally, J.J. Arias is my pen name. I do have a day job, and due to the industry I’m in, I can’t write under my given name. Although who knows, maybe one day I can write full-time and come out of the … office? I am a Scorpio woman (I know, I know, but I’m a nice one I PROMISE) happily married to a uniquely wonderful Cancer lady. Together we have several fur babies of the feline and canine varieties.
So, here I am, and I hope you enjoy my writing! I’m very open to thoughts, comments, critiques, and knock-knock jokes, so please feel free to message me with any of the above – or anything else you would like to say!
I am an independent author writing about fictional lesbians of all varieties.
My writing journey began with fan faction, and as much as I LOVED being part of a community of super fans, I got tired of working with other people’s characters to tell my stories. I started asking myself: Why should we string together pieces of subtext when our community deserves well-developed main-text about LBGT people and those who love them! So, that is what I aim to deliver.
If you want to know a little more about me personally, J.J. Arias is my pen name. I do have a day job, and due to the industry I’m in, I can’t write under my given name. Although who knows, maybe one day I can write full-time and come out of the … office? I am a Scorpio woman (I know, I know, but I’m a nice one I PROMISE) happily married to a uniquely wonderful Cancer lady. Together we have several fur babies of the feline and canine varieties.
So, here I am, and I hope you enjoy my writing! I’m very open to thoughts, comments, critiques, and knock-knock jokes, so please feel free to message me with any of the above – or anything else you would like to say!
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Displaying 1 - 30 of 92 reviews
July 13, 2021
How I’ve missed reading a really good book. I’m so happy I found this one and gave it a chance. Simply amazing. I was hooked right from the start. The slow-burn romance and the fact that I was always on the edge of my seat because of the plot and the drama I kept imagining would happen were simply the right ingredients for this amazing story. I love both MCs so much and their story and I’m so happy everything got sorted in the end and they got their well deserved happy ending. 100% recommend
July 20, 2021
4.5 ⭐️ - surprisingly good. Writing was top notch. Story and characters were interesting and engaging. The angst was believable and excruciating in the best way. Highly recommend.
August 31, 2024
J.J. Arias is one of my favorite authors, and I’ve enjoyed all of her books (of the ones I’ve read anyways). Her writing is consistently engaging, with vivid world-building and well-crafted characters that draw you in from the first page. I found many aspects of Undercover Madam captivating, but one element bothered me: Alex was kept in the dark about Charlotte's true identity for nearly 90% of the book.
It was frustrating that Charlotte waited so long—months after they had slept together and fallen for each other—before revealing that she was sent to infiltrate Alex’s business. The fact that Charlotte lied to her for almost a year felt manipulative, which made parts of the story difficult to read.
That said, the last few chapters of the book did redeem the story to some extent. Without giving too much away, Charlotte’s internal struggle with her deception was evident, and I appreciated that she faced consequences for her actions. Ultimately, Alex’s forgiveness led to a sweet and satisfying HEA, which helped soften the impact of the earlier deception.
It was frustrating that Charlotte waited so long—months after they had slept together and fallen for each other—before revealing that she was sent to infiltrate Alex’s business. The fact that Charlotte lied to her for almost a year felt manipulative, which made parts of the story difficult to read.
That said, the last few chapters of the book did redeem the story to some extent. Without giving too much away, Charlotte’s internal struggle with her deception was evident, and I appreciated that she faced consequences for her actions. Ultimately, Alex’s forgiveness led to a sweet and satisfying HEA, which helped soften the impact of the earlier deception.
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August 11, 2021DNF at 13% (6 out of 46 chapters + epilogue).
No rating 'cause this review is only meant to explain why I stopped reading this early. Treat it merely as a first impression of the book, and take it with a grain of salt.
I found the blatant flirting between the MCs to be on the excessive side, considering the novelty of their acquaintance. Constantly lusting for and openly flirting with one's new boss are simply not how I realistically see someone would conduct themselves at their new job, not to mention its lack of appropriateness. Even when the mood doesn't call for it, the MCs' conversations were riddled with innuendos. In other words, a case of too much, too soon.
But coming from the high of reading The Fifth Surgeon, my expectations for chemistry buildup might be skewed.
Others have commented about the story being great though. So if the mood strikes, maybe I'll revisit this book in the future.
About the cover: Assuming the model is meant to portray Alexandra, she looks too young to be 45 years old.
No rating 'cause this review is only meant to explain why I stopped reading this early. Treat it merely as a first impression of the book, and take it with a grain of salt.
I found the blatant flirting between the MCs to be on the excessive side, considering the novelty of their acquaintance. Constantly lusting for and openly flirting with one's new boss are simply not how I realistically see someone would conduct themselves at their new job, not to mention its lack of appropriateness. Even when the mood doesn't call for it, the MCs' conversations were riddled with innuendos. In other words, a case of too much, too soon.
But coming from the high of reading The Fifth Surgeon, my expectations for chemistry buildup might be skewed.
Others have commented about the story being great though. So if the mood strikes, maybe I'll revisit this book in the future.
About the cover: Assuming the model is meant to portray Alexandra, she looks too young to be 45 years old.
September 21, 2026
I found this fabulous book on my TBR shelves! What a beautiful age gap love story! When Charlotte is offered a chance to get in the FBI if she infiltrates a spa business and bust the owner, a madam. Char gets the opportunity to apply as an accountant.Then she meets Alexandra, the owner of the spa. She's gorgeous! So, Char takes on the task of seducing Alex. What she didn't anticipate was falling in love with her.
The heat is off the chart! But when one of the johns goes to the police Char is put in a bad spot!
I LOVE THIS BOOK!!5 stars!!
The heat is off the chart! But when one of the johns goes to the police Char is put in a bad spot!
I LOVE THIS BOOK!!5 stars!!
July 12, 2021
I’m always thrilled when JJ Arias publishes a new tale and while she stuck with the age-gap theme she writes so well, this one was fortunately not an enemies to lovers romance.
Charlotte only cared about two people in the world, Jayson (her brother) and herself. All she ever wanted to do was become a forensic accountant for the FBI, and all she had to do was infiltrate a madam’s fortress. Charlotte was totally on board with exposing the underworld empire of Alexandra Leon, until they came face to face at her job interview and the immediate chemistry was off the charts. As the layers of Alex were slowly peeled back, the reader couldn’t help but fall in love with her and hope that Charlotte wouldn’t betray her trust. I honestly love everything about this book and have most definitely put it on my reread pile!
Charlotte only cared about two people in the world, Jayson (her brother) and herself. All she ever wanted to do was become a forensic accountant for the FBI, and all she had to do was infiltrate a madam’s fortress. Charlotte was totally on board with exposing the underworld empire of Alexandra Leon, until they came face to face at her job interview and the immediate chemistry was off the charts. As the layers of Alex were slowly peeled back, the reader couldn’t help but fall in love with her and hope that Charlotte wouldn’t betray her trust. I honestly love everything about this book and have most definitely put it on my reread pile!
January 20, 2025
Absolutely enjoyed it! I especially liked the grey areas presented in the story and I think the author did a great job with them. My inspiration to move this one up my tbr list were Ada and Minna Everleigh, and I'd like to think the two would have appreciated the class and respect Alex rightfully gives to sex work.
July 14, 2025
I read this in a single day—couldn’t put it down. JJ Arias has done it again with another slam dunk that proves just how addictive her storytelling is. I’m convinced at this point that her take on romance is my exact wavelength.
As with her other novels, Arias masterfully blends high-stakes thrills with sizzling chemistry. The plot is gripping from the start, keeping you on your toes. And the ending leaves you with a full heart and a big, satisfied grin.
If you're already a fan of Arias, this one is a no-brainer. If you're not—this is the perfect place to start. Just be warned: you may not be able to stop.
As with her other novels, Arias masterfully blends high-stakes thrills with sizzling chemistry. The plot is gripping from the start, keeping you on your toes. And the ending leaves you with a full heart and a big, satisfied grin.
If you're already a fan of Arias, this one is a no-brainer. If you're not—this is the perfect place to start. Just be warned: you may not be able to stop.
October 4, 2021
I have to admit that I picked this up a few months ago and then stopped reading it at about 40% through. I think at the time it wasn't a storyline I wanted to invest time in, but a few days ago I decided to pick it back up again. I'm glad I did.
This book starts off quite slow, and although J.J. Arias writes amazing slow-burns, this felt slow in a different way. Charlotte's doggedness towards infatuating Alex's business was so predatory and the chemistry initially between them felt so fake and cumbersome.
But, the story shifts once Charlotte and Alex become romantically involved. The chemistry begins to feel very real and organic, and my engagement with the romance kicked in as I kept wondering how Charlotte would get herself out of the mess she created. The way this was all resolved was great, and again, it felt very realistic and well-concluded.
All in all, I liked this book and I'm very glad I picked it back up on a whim.
This book starts off quite slow, and although J.J. Arias writes amazing slow-burns, this felt slow in a different way. Charlotte's doggedness towards infatuating Alex's business was so predatory and the chemistry initially between them felt so fake and cumbersome.
But, the story shifts once Charlotte and Alex become romantically involved. The chemistry begins to feel very real and organic, and my engagement with the romance kicked in as I kept wondering how Charlotte would get herself out of the mess she created. The way this was all resolved was great, and again, it felt very realistic and well-concluded.
All in all, I liked this book and I'm very glad I picked it back up on a whim.
July 12, 2021
JJ Arias is killin' it in this book! She slays the slow-burn romance against a backdrop of underworld intrigue in the sex industry. With a deft touch for steamy romance and a knowledgeable application of criminal cat and mouse, JJ delivers a nail-biter to the end with a surprising and satisfying conclusion. This book rings all the bells! Favorite quote: "She’s got this detached goddess energy that’s very alluring." And JJ Arias does!
July 13, 2023
3,25/5
Idk if I didn't enjoyed this as much as I thought because I wasn't in the right mood or just because it wasn't the right book for me.
The beginning was okay,Charlotte is supposed to get this job to Alex's business (let's go with that)and go undercover to find out every evidence she can get so she could prove that Alex it's part of a illegal business. Their interactions at first reminded me of the Turkish dramas I used to watch when I was 12 year old.
Charlotte was a fun character but I think she was coming too strong too soon.
And the only realistic thing in this book was probably their relationship, it didn't set my expectations for love higher or anything, It wasn't a life changing love-story or anything, just a normal developing relationship (probably why I was bored sometimes (I'm mentally ill*))
But overall kinda liked it.🤞
Idk if I didn't enjoyed this as much as I thought because I wasn't in the right mood or just because it wasn't the right book for me.
The beginning was okay,Charlotte is supposed to get this job to Alex's business (let's go with that)and go undercover to find out every evidence she can get so she could prove that Alex it's part of a illegal business. Their interactions at first reminded me of the Turkish dramas I used to watch when I was 12 year old.
Charlotte was a fun character but I think she was coming too strong too soon.
And the only realistic thing in this book was probably their relationship, it didn't set my expectations for love higher or anything, It wasn't a life changing love-story or anything, just a normal developing relationship (probably why I was bored sometimes (I'm mentally ill*))
But overall kinda liked it.🤞
December 1, 2021
There was no dismissing Charlotte now. She was lightning cracking in the sky. A fleeting warning before the unstoppable storm.
3.5 stars. This was such a good, fleshed out romance! That's the thing that's lingering with me as I just finished: the fact that I don't read a lot of standalone romance novels that take their time with the characters and follow them for upwards of a year, and let a full, organic relationship really develop. This is about an accountant, Charlotte, who is deputised by the police to go undercover at an upscale spa that also houses a brothel. She ends up falling for Alex, the woman who owns the business. Though this isn't really a slow burn, the book allows for the passage of time, and lets the reader see how the chemistry between them grows into something deeper. Given the plot, there's some good angst and tension. I really liked both main characters; they were compelling and engaging and really made me believe in the romance. Some of the stuff in the last third gave me so many butterflies!! There's an age gap as well, and it's handled in the way I like best: you can tell they have their differences, but they're both mature adults. I also really liked how the sex work aspect was handled, and how Alex ran her business.
Sometimes the characters' internal thoughts and monologues didn't feel realistic or convincing. Like, at a very early point, Alex was thinking about what it would be like if Charlotte was her partner, which seemed like a weird thing to be on her mind. I kinda wish we'd spent more time with Jay and Stephanie, since they were so important to our main characters (especially Stephanie; I feel like she was barely there). The writing was good, though a couple things did trigger my editing brain hardcore.
Really sweet overall though; I can't wait to give this author another try.
April 8, 2024
If you're following my reviews, you know I'm a mega fan of the wonderful JJ Arias. I loved loved this forbidden age-gap romance. Her writing continues to astound me as I make my way through her backlist of titles. This is a fantastic slow-burn romance. Arias did an amazing job with this unique storyline. I'll tell ya, this one was a little more angsty for me because the relationship starts out under false pretenses. Lines quickly get blurred and both Alex and Charlotte catch feelings. I loved Alex's character. She's a powerhouse and gets s#it done, but I love her softer layers. Charlotte is sharp and motivated for her own outcome but quickly sees that Alex more than she seems. The chemistry between these two is fantastic (Arias knows what she's doing with these age gaps). This book had me on the edge of my seat trying to figure out how we were going to get an HEA for these two fierce femmes and oh what a ride!!
Highly recommend for Arias fans everywhere!!
Highly recommend for Arias fans everywhere!!
May 22, 2023
_____
Too descriptive, but I guess I thought that because I was bored and didn't care about the characters or the story.
[Read for my maze]
Task: Read a book with a palindrome over 4 letters in the title
March 11, 2026
Alex was just a Queen! What a loveable character.. my heart actually hurt for her.
November 25, 2024
3.5 ⭐️. Chemistry between the two m/c’s was reallyy good. Found it hard to settle into the story when we know the whole time that the confession of being undercover, and the inevitable fall out, has to come at some point. Storyline just didn’t really grab me in the end
July 7, 2021
Good book. I was highly engaged in how Charlotte was going to handle everything. Also didn’t follow the typical timeline for a romance which was nice.
July 20, 2022
(alex is so hot...)
January 16, 2023
I did enjoy this, as with all J.J Arias works so far, but I could not get a specific detail out of my head (and so, I could not give this a five star rating).
Charlotte’s dream is to be a forensic accountant (or something to that effect) in the FBI. And not once did she seem to mourn the fact that she was giving up that dream. Like, this is not a big deal in the overall scheme of the story, but I would have imagined she would make it a slightly more important loss in her life?
It probably does not help that I read this in a haze of sickness, so I could not enjoy it to the fullest (constantly dozing or just finding myself disconnected to the writing as a whole). Unfortunate, as I do enjoy J.J. Arias books and would love to say I give them my full attention!! Alas!!
Charlotte’s dream is to be a forensic accountant (or something to that effect) in the FBI. And not once did she seem to mourn the fact that she was giving up that dream. Like, this is not a big deal in the overall scheme of the story, but I would have imagined she would make it a slightly more important loss in her life?
It probably does not help that I read this in a haze of sickness, so I could not enjoy it to the fullest (constantly dozing or just finding myself disconnected to the writing as a whole). Unfortunate, as I do enjoy J.J. Arias books and would love to say I give them my full attention!! Alas!!
September 27, 2026
My favorite part of this was the middle. Alex and Charlotte together were fantastic, their time together (such as the Barcelona trip) was amazing, and the story drama hanging over Charlotte’s head kept things interesting. I was a bit less sold on the start and the end . Though it’s not my favorite JJ Arias book (she has so many outstanding ones to pick from), I still might read it again for that amazing middle section.
November 18, 2024
3.5⭐
The first half was a 4 star and the second half more like a 2.5.
I really liked Alex, Charlotte was fine and I didn't care about any of the side characters.
They were sweet together and I liked their relationship.
Every deep or sweet conversation they had turned into sex, which really annoyed me.
I feel like nothing really happened in the book.
Things were mentioned and never really revisited.
The whole plot was wrapped up so strangely and boring.
This could have been a normal romance without the whole illegal business thing and it would've been basically the same.
Also, the pacing really threw me off.
The first half was a 4 star and the second half more like a 2.5.
I really liked Alex, Charlotte was fine and I didn't care about any of the side characters.
They were sweet together and I liked their relationship.
Every deep or sweet conversation they had turned into sex, which really annoyed me.
I feel like nothing really happened in the book.
Things were mentioned and never really revisited.
The whole plot was wrapped up so strangely and boring.
This could have been a normal romance without the whole illegal business thing and it would've been basically the same.
Also, the pacing really threw me off.
June 23, 2023
I don't know what it is about this book, but it didn't have the effect I thought it would have had.
The book is not bad, but I found it quite boring as it was over-descriptive. I don't really have much to say about the book. I just noticed that, for some reason, I couldn't connect with the characters properly.
The plot of the book was a good idea, but I noticed once again it dragged on, and that caused the book to be boring.
Rating:
3/5
⭐️⭐️⭐️/⭐️⭐️⭐️⭐️⭐️
The book is not bad, but I found it quite boring as it was over-descriptive. I don't really have much to say about the book. I just noticed that, for some reason, I couldn't connect with the characters properly.
The plot of the book was a good idea, but I noticed once again it dragged on, and that caused the book to be boring.
Rating:
3/5
⭐️⭐️⭐️/⭐️⭐️⭐️⭐️⭐️
July 10, 2021
I'll admit I, prude that I am, was ambivalent about the subject matter of this story but wow! I so enjoyed it. The characters were as different as two characters could get but they worked. I really like this author's writing and this, although different, is a really great read. Waiting for her next…
August 18, 2022
Super sexy and sultry like a sexy sapphic indie movie
Some forbidden flair as the FMC is working for the FBI to investigate the other FMC whom might be a madam.
They also have an age gap the madam is older and wiser, but can't resist the new accountant.
I love the slow burn aspect of the story and the steamy scenes are so sexy.
A great read!
Some forbidden flair as the FMC is working for the FBI to investigate the other FMC whom might be a madam.
They also have an age gap the madam is older and wiser, but can't resist the new accountant.
I love the slow burn aspect of the story and the steamy scenes are so sexy.
A great read!
January 20, 2023
alexcharlotte 3✨ 3🌶
although this was lovely, i didn’t connect at all with the characters. i think i’m just not used to book in third person… it was different but not bad.
i thought the paced was kinda slow.
although this was lovely, i didn’t connect at all with the characters. i think i’m just not used to book in third person… it was different but not bad.
i thought the paced was kinda slow.
July 11, 2021
Held My Breath the Entire Book
I have to say, this is my favorite J.J. Arias book to date. The tension, the love, and the wonder if love will truly win out had me on the edge and holding my breath. Thank you J.J. for the ride!
I have to say, this is my favorite J.J. Arias book to date. The tension, the love, and the wonder if love will truly win out had me on the edge and holding my breath. Thank you J.J. for the ride!
October 27, 2025
Predictable but a fun ride nonetheless
Displaying 1 - 30 of 92 reviews