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Behind a Locked Door
She opened the wrong door. Now her life will never be the same.
When Lucy Foster visits her old friend, she doesn't expect to hear a baby crying behind a locked cellar door. But what she finds shatters everything she thought she a terrified teenage girl and a newborn, hidden away like a secret shame.
As Lucy's quiet life spirals into a media frenzy, and the town turns against her, one thing becomes clear—someone is watching. And they want Lucy to stop helping the girl in the cellar.
Because the truth is darker than anyone imagines. And unlocking it may cost Lucy everything.
When Lucy Foster visits her old friend, she doesn't expect to hear a baby crying behind a locked cellar door. But what she finds shatters everything she thought she a terrified teenage girl and a newborn, hidden away like a secret shame.
As Lucy's quiet life spirals into a media frenzy, and the town turns against her, one thing becomes clear—someone is watching. And they want Lucy to stop helping the girl in the cellar.
Because the truth is darker than anyone imagines. And unlocking it may cost Lucy everything.
Audible Audio
Published September 4, 2025
1011 people are currently reading
5006 people want to read
About the author
Sarah A. Denzil
46 books2,532 followersSarah A. Denzil is a Wall Street Journal bestselling suspense writer. She is also known as young adult author Sarah Dalton.
Sarah lives in Yorkshire with her partner, enjoying the scenic countryside and rather unpredictable weather.
She is the author of international bestselling psychological thriller SILENT CHILD, which topped the bestseller lists on Amazon in the US, UK and Australia.
You can read now read AIDEN'S STORY, a short story and sequel to SILENT CHILD. It's completely free here: https://dl.bookfunnel.com/n7lb74chp3
Find out more at: http://www.sarahdenzil.com/
Join the newsletter for updates: http://eepurl.com/cwAmZD
Follow her on Facebook: https://www.facebook.com/sarahadenzil
Check out her Instagram page:
https://www.instagram.com/sarahadenzil/
Email: sarah@sarahdenzil.com
Sarah lives in Yorkshire with her partner, enjoying the scenic countryside and rather unpredictable weather.
She is the author of international bestselling psychological thriller SILENT CHILD, which topped the bestseller lists on Amazon in the US, UK and Australia.
You can read now read AIDEN'S STORY, a short story and sequel to SILENT CHILD. It's completely free here: https://dl.bookfunnel.com/n7lb74chp3
Find out more at: http://www.sarahdenzil.com/
Join the newsletter for updates: http://eepurl.com/cwAmZD
Follow her on Facebook: https://www.facebook.com/sarahadenzil
Check out her Instagram page:
https://www.instagram.com/sarahadenzil/
Email: sarah@sarahdenzil.com
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Displaying 1 - 30 of 473 reviews
December 10, 2025
At times suspenseful and thrilling, but I didn’t ‘buy’ it
Read
August 26, 2025This book was born from reminiscing about books I've already written and trying to come up with something both fresh and familiar. It was while thinking about what made Silent Child such a huge hit that I came up with Behind a Locked Door.
Both are about the aftermath of a child locked away from the world. Both are about a mother trying to do what's best for her teenage son. But they are both completely different books in tone and plot.
I can't wait to share this one with you all! It's dark, creepy, and psychological. I love these characters and I'm so happy to have brought them to life in this book!
I think Lucy is a fantastic character, but Alice might just become a fan favourite. There are more than a few twists in the tale, some you may suspect, others probably not. You'll certainly enjoy the ride though!
Enjoy! :)
Sarah
Both are about the aftermath of a child locked away from the world. Both are about a mother trying to do what's best for her teenage son. But they are both completely different books in tone and plot.
I can't wait to share this one with you all! It's dark, creepy, and psychological. I love these characters and I'm so happy to have brought them to life in this book!
I think Lucy is a fantastic character, but Alice might just become a fan favourite. There are more than a few twists in the tale, some you may suspect, others probably not. You'll certainly enjoy the ride though!
Enjoy! :)
Sarah
September 22, 2025
This book gets a 4.25 stars 🌟 from me. This book had some serious twists and turns that I didn't see coming. Very engaging and action-packed that it was hard to put down.
October 31, 2025
This was an entertaining short suspense thriller. The writing was good, there was not graphic violence, there were surprises. It uses the trope of the girl with the personality disorder, and while it is predictable, it really was an entertaining audiobook experience. About 3-4 hours listen.
September 21, 2025
I’ve read and liked a few of Sarah A. Denzil’s books, so I was excited to pick up Behind a Locked Door. This is very much a domestic thriller, full of hidden secrets and proof that some doors really should stay closed. The pacing drags a bit in the middle and a few twists were predictable, but I still found myself turning the pages and enjoying the ride. Not my favourite from her, but a solid, engaging read. 3 stars.
September 14, 2025
3.5 🌟
The title was what initially drew me to this book. I've read books by Sarah A. Denzel before, and they were pretty good. The story is crazy and unsettling. Couldn't decide whether to round up or round down the stars, but it did keep my attention til the end, so I rounded up. It's not the greatest story, but it's decent enough!
The title was what initially drew me to this book. I've read books by Sarah A. Denzel before, and they were pretty good. The story is crazy and unsettling. Couldn't decide whether to round up or round down the stars, but it did keep my attention til the end, so I rounded up. It's not the greatest story, but it's decent enough!
November 1, 2025
How far will a mother go to protect her son?
This freaking book had me on the edge of my seat!!! it was so good. The plot twist was good. The intensity of the drama was great.
As we got closer to the end of the book, the drama picked up in a way that had me spinning!
This freaking book had me on the edge of my seat!!! it was so good. The plot twist was good. The intensity of the drama was great.
As we got closer to the end of the book, the drama picked up in a way that had me spinning!
September 2, 2025
I must admit that I came away quite disappointed with this one. Sarah A. Denzil is usually an author who wows me, who pulls the rug out from under my feet, or who gives me that sharp intake of breath moment when the twist finally lands. Sadly, this just didn’t deliver in the same way. From the very start, it felt a little flat, as though the edge had been blunted, and that sense of originality I usually associate with her work was missing.
It’s not even that I went in with high expectations. When I first picked it up, I’d actually forgotten who had written it and assumed it was by someone else. The style had that generic, almost “anyone could have written this” tone, and when I checked and realised it was Denzil, I was surprised. By any other author, this would have been fine — a serviceable thriller with some tension and an ending that ties things up neatly — but because it was hers, I felt let down.
The twist was far too obvious. I clocked it very early on, and once you see where it’s going, the suspense drains away. The pacing didn’t help either; it was quite slow in the middle, and I found myself struggling to keep turning the pages. Normally, I’ll reach for one of her books eagerly, wanting to know what happens next, but here I was dragging my feet and leaving it untouched for days at a time. That’s never a good sign with a thriller.
That said, I will give credit where it’s due — the ending was handled well. It felt more engaging, and the threads came together in a satisfying way. It didn’t redeem the whole experience, but it did leave me with a sense of closure. I just wish the journey to get there had been more compelling.
If this had been my first Denzil book, I think I’d probably have rated it as a decent, middle-of-the-road thriller. Nothing spectacular, but perfectly fine to pass the time. The problem is that I know what she’s capable of. I’ve read her at her best, and I know how sharp, clever and shocking her writing can be. Compared to that, this felt watered down.
So, while new readers may enjoy it as an introduction, for long-time fans it might come across as underwhelming. I wanted more twists, more tension, and more of that unforgettable punch that Denzil usually delivers. This time, unfortunately, it just didn’t happen.
It’s not even that I went in with high expectations. When I first picked it up, I’d actually forgotten who had written it and assumed it was by someone else. The style had that generic, almost “anyone could have written this” tone, and when I checked and realised it was Denzil, I was surprised. By any other author, this would have been fine — a serviceable thriller with some tension and an ending that ties things up neatly — but because it was hers, I felt let down.
The twist was far too obvious. I clocked it very early on, and once you see where it’s going, the suspense drains away. The pacing didn’t help either; it was quite slow in the middle, and I found myself struggling to keep turning the pages. Normally, I’ll reach for one of her books eagerly, wanting to know what happens next, but here I was dragging my feet and leaving it untouched for days at a time. That’s never a good sign with a thriller.
That said, I will give credit where it’s due — the ending was handled well. It felt more engaging, and the threads came together in a satisfying way. It didn’t redeem the whole experience, but it did leave me with a sense of closure. I just wish the journey to get there had been more compelling.
If this had been my first Denzil book, I think I’d probably have rated it as a decent, middle-of-the-road thriller. Nothing spectacular, but perfectly fine to pass the time. The problem is that I know what she’s capable of. I’ve read her at her best, and I know how sharp, clever and shocking her writing can be. Compared to that, this felt watered down.
So, while new readers may enjoy it as an introduction, for long-time fans it might come across as underwhelming. I wanted more twists, more tension, and more of that unforgettable punch that Denzil usually delivers. This time, unfortunately, it just didn’t happen.
October 5, 2025
this was really easy to read and get through, but that’s really all it had going for it, unfortunately. i didn’t care about any of the characters, the twist was extremely obvious, and the writing wasn’t my favorite. it wasn’t even really bad or anything, but i was mainly just bored. even when i guess plot twists early on, which i do a lot in thrillers, there’s enough going on in the story to keep me engaging and enjoying the build up. this one just seemed to miss the mark for me i guess.
2.5 stars
2.5 stars
September 27, 2025
SO MANY PLOT HOLES.
September 7, 2025
Fast paced but I figured out the twists pretty early on.
September 7, 2025
Very predictable for me & the characters annoyed me massively me but very quick fast paced read.
January 5, 2026
3.5 Stars
I really enjoyed the first 3/4 of this novel but I am still not sure how I feel about the ending. An interesting premise and a little bit predictable.
Decent read.
I really enjoyed the first 3/4 of this novel but I am still not sure how I feel about the ending. An interesting premise and a little bit predictable.
Decent read.
August 20, 2025
Thank you to NetGalley and Victory Editing for this ARC.
Wow—this was such a gripping read! I flew through Behind a Locked Door in one sitting. The pacing was fast, the suspense was constant, and I loved the multiple POVs—especially the contrast between Lucy’s protective instincts and Alice’s chilling, emotionless perspective. It added a real psychological edge to the story.
Even the minor characters had depth and added to the tension. Sarah Denzil is a new author to me, but I’ll definitely be reading more from her!
Wow—this was such a gripping read! I flew through Behind a Locked Door in one sitting. The pacing was fast, the suspense was constant, and I loved the multiple POVs—especially the contrast between Lucy’s protective instincts and Alice’s chilling, emotionless perspective. It added a real psychological edge to the story.
Even the minor characters had depth and added to the tension. Sarah Denzil is a new author to me, but I’ll definitely be reading more from her!
October 16, 2025
FEELS DIFFERENT BUT SAME WRITER AND I'M HERE FOR IT!
I haven’t read most of Sarah A. Denzil’s books, but so far this is the best. The Secret Sister wasn’t bad either. Her stories never feel repetitive and I honestly think she’s very underrated in the crime and thriller space.
I like that this book doesn’t waste time getting into the plot. The author slows things down just enough to let you get used to the characters.
You don’t have to wait until the last chapter to meet the villain. Everything unfolds right in front of you even though it’s hiding in plain sight. The story doesn’t rely on one big twist which I appreciated.
Is it predictable? Yes.
Is it a solid story? Not really. There are a few inconsistencies. For example,
Overall not a bad thriller
I haven’t read most of Sarah A. Denzil’s books, but so far this is the best. The Secret Sister wasn’t bad either. Her stories never feel repetitive and I honestly think she’s very underrated in the crime and thriller space.
I like that this book doesn’t waste time getting into the plot. The author slows things down just enough to let you get used to the characters.
You don’t have to wait until the last chapter to meet the villain. Everything unfolds right in front of you even though it’s hiding in plain sight. The story doesn’t rely on one big twist which I appreciated.
Is it predictable? Yes.
Is it a solid story? Not really. There are a few inconsistencies. For example,
Overall not a bad thriller
August 19, 2025
This was a wild ride from beginning to end! When Lucy visits an old friend, she find a teenage girl and her newborn locked in the basement. Lucy tries to help her as she has no family and soon her life spirals out of control….
This was a quick read with lots of twists and turns. Things are not what you expect so hold on tight!
This was a quick read with lots of twists and turns. Things are not what you expect so hold on tight!
December 3, 2025
Qué cosa tan espectacular es este libro. No hubo un solo capítulo en el que no estuviera completamente enganchada con el misterio; lo devoré y siento que lo habría terminado todavía más rápido si hubiera estado desocupada. Me encantó de verdad, me dejó con muchísimas ganas de seguir leyendo a la autora y, honestamente, se convirtió en el primer libro que recomiendo cada vez que alguien me pide una sugerencia de lectura.
August 25, 2025
Behind a Locked Door is an unsettling, gripping psychological thriller that kept me hooked from the first page. Sarah A. Denzil delivers a tense and twisty story that explores secrets, lies, and the terrifying consequences of opening the wrong door.
The story follows Lucy Foster, whose life takes a shocking turn when she visits an old friend and hears a baby crying behind a locked cellar door. What she discovers—a terrified teenage girl and a newborn hidden away—completely shatters her world. From that moment on, Lucy becomes tangled in a dangerous web of secrets, public scrutiny, and fear. As the media frenzy grows and the town begins to turn against her, she realises that someone is watching her closely… and they’ll do anything to stop her from helping the girl in the cellar.
I really enjoyed how the tension builds throughout the book. Denzil’s writing creates an atmosphere of dread that lingers on every page, and I found myself constantly questioning who to trust. Lucy is a well-developed character, and I liked how her emotions—her shock, fear, and determination—felt authentic. The pacing is strong, with plenty of twists that kept me invested, though a couple of them were slightly predictable.
What stood out to me was the exploration of morality—how far someone is willing to go to uncover the truth and help others, even when it puts their own life in danger. The darkness of the story, combined with the emotional weight of what Lucy uncovers, made this a compelling and thought-provoking read.
While I didn’t give it a full five stars—mostly because there were a few slower moments and I guessed one of the major reveals early on—it’s still a fantastic read. If you enjoy dark, suspenseful stories with secrets buried deep, Behind a Locked Door is absolutely worth picking up.
https://featzreviews.com/behind-a-loc...
The story follows Lucy Foster, whose life takes a shocking turn when she visits an old friend and hears a baby crying behind a locked cellar door. What she discovers—a terrified teenage girl and a newborn hidden away—completely shatters her world. From that moment on, Lucy becomes tangled in a dangerous web of secrets, public scrutiny, and fear. As the media frenzy grows and the town begins to turn against her, she realises that someone is watching her closely… and they’ll do anything to stop her from helping the girl in the cellar.
I really enjoyed how the tension builds throughout the book. Denzil’s writing creates an atmosphere of dread that lingers on every page, and I found myself constantly questioning who to trust. Lucy is a well-developed character, and I liked how her emotions—her shock, fear, and determination—felt authentic. The pacing is strong, with plenty of twists that kept me invested, though a couple of them were slightly predictable.
What stood out to me was the exploration of morality—how far someone is willing to go to uncover the truth and help others, even when it puts their own life in danger. The darkness of the story, combined with the emotional weight of what Lucy uncovers, made this a compelling and thought-provoking read.
While I didn’t give it a full five stars—mostly because there were a few slower moments and I guessed one of the major reveals early on—it’s still a fantastic read. If you enjoy dark, suspenseful stories with secrets buried deep, Behind a Locked Door is absolutely worth picking up.
https://featzreviews.com/behind-a-loc...
September 10, 2025
3.5 ⭐️
This gripping thriller had me hooked from the very first chapter, blending mystery, suspense, and a chilling premise.
When Lucy Foster opened a locked cellar door, she uncovered a terrified teen and her newborn hidden inside. What started as a shocking discovery quickly spiraled into danger as Lucy faced town gossip, media chaos, and a threat that someone would do anything to keep the truth buried.
There were parts of Denzil’s story that pulled me in and others that didn’t land as strongly. From the shocking moment in the cellar, I was immediately hooked—the pacing stayed sharp, the tension held throughout, and the twists kept me engaged while still making me care about Lucy and the choices she faced. Some of the side characters felt underdeveloped, and a few reveals were easier to see coming, but the intensity and central mystery ultimately made this an entertaining psychological thriller.
In the end, Behind a Locked Door delivered a dark, gripping story that was both unsettling and addictive—a psychological thriller that kept me guessing until the truth was finally revealed. (Audio)
This gripping thriller had me hooked from the very first chapter, blending mystery, suspense, and a chilling premise.
When Lucy Foster opened a locked cellar door, she uncovered a terrified teen and her newborn hidden inside. What started as a shocking discovery quickly spiraled into danger as Lucy faced town gossip, media chaos, and a threat that someone would do anything to keep the truth buried.
There were parts of Denzil’s story that pulled me in and others that didn’t land as strongly. From the shocking moment in the cellar, I was immediately hooked—the pacing stayed sharp, the tension held throughout, and the twists kept me engaged while still making me care about Lucy and the choices she faced. Some of the side characters felt underdeveloped, and a few reveals were easier to see coming, but the intensity and central mystery ultimately made this an entertaining psychological thriller.
In the end, Behind a Locked Door delivered a dark, gripping story that was both unsettling and addictive—a psychological thriller that kept me guessing until the truth was finally revealed. (Audio)
November 9, 2025
3.5 🌟
A well written book! I really love Sarah, she is one of my favourite British authors. I do feel like some parts of this book did drag.
With the end twist, it wasn't as big as it could of been. In all honesty I totally forgot who that person was 😩😂
A well written book! I really love Sarah, she is one of my favourite British authors. I do feel like some parts of this book did drag.
With the end twist, it wasn't as big as it could of been. In all honesty I totally forgot who that person was 😩😂
November 10, 2025
Sarah A. Denzil is definitely one of those writers I am grateful for. Her works usually entertain me quite a bit, they are subtly twisty and well written.
This one was not my top book of hers, but still found it engaging and flowing well. I ate it up. I kind of wished for a different twist, but oh well, my mind works differently and maybe it would’ve been too obvious!
I have a soft spot for weird kids in books, so might be the reason why I liked it too.
This one was not my top book of hers, but still found it engaging and flowing well. I ate it up. I kind of wished for a different twist, but oh well, my mind works differently and maybe it would’ve been too obvious!
I have a soft spot for weird kids in books, so might be the reason why I liked it too.
September 8, 2025
Wow this wastes no time getting right into it! An addictive page turner for sure. We have twists and turns and all the suspense! I’ll definitely be checking out more from this author. Highly recommend!
September 18, 2025
The poor protagonist in this book suffers way more than she deserves in this thriller! She’s a good citizen, immediately calling the police when she hears a woman locked in a basement. But, boy, does she regret that decision! What follows are harrowing events that threaten both her and her son’s lives. I enjoyed this book as it read quickly and the story was plain disturbing fun!
October 7, 2025
Perfectly acceptable little popcorn thriller to listen to while doing chores.
November 7, 2025
This book is ridiculous. Plot holes aside, I’ve encountered my fair share of insufferable, dumb thriller narrators, but this one really got on my nerves. The other narrators that would occasionally pop in didn’t really add anything to the story either and had almost no personality. The writing was really redundant. Everything Lucy was thinking was said three or four different ways. It really made me hate Lucy and the writing. It felt like the author was writing for an audience she didn’t trust to understand the story.
The twists were so obvious and in your face. Lucy was acting simultaneously like a helicopter parent and naïve one. For some reason she wanted to believe the best of everyone else and the worst of Theo. Then she wonders why he’s acting a little rebellious after she lied to his face multiple times. I also thought the fact that she literally teaches psychology would make some impact on her ability to make decent evaluations on healthy and unhealthily behaviors, but alas that was expecting too much.
Alsooo not all Psychopaths are sadists! For the amount of psychopaths in this book, it would have been far more interesting if they weren’t all truly horrible people just born to be evil. Even if certain aspects of psychopathy are genetic, environmental conditions play a huge part in their development, and for multiple generations to end up the same amount sadistic after being raised in drastically different conditions just doesn’t make sense. This book clearly didn’t have a true understanding of any kind of psychology and even I myself who is certainly no expert was picking out things that just didn’t make sense the entire time. There are far better free thrillers on Audible rather than this one.
The twists were so obvious and in your face. Lucy was acting simultaneously like a helicopter parent and naïve one. For some reason she wanted to believe the best of everyone else and the worst of Theo. Then she wonders why he’s acting a little rebellious after she lied to his face multiple times. I also thought the fact that she literally teaches psychology would make some impact on her ability to make decent evaluations on healthy and unhealthily behaviors, but alas that was expecting too much.
Alsooo not all Psychopaths are sadists! For the amount of psychopaths in this book, it would have been far more interesting if they weren’t all truly horrible people just born to be evil. Even if certain aspects of psychopathy are genetic, environmental conditions play a huge part in their development, and for multiple generations to end up the same amount sadistic after being raised in drastically different conditions just doesn’t make sense. This book clearly didn’t have a true understanding of any kind of psychology and even I myself who is certainly no expert was picking out things that just didn’t make sense the entire time. There are far better free thrillers on Audible rather than this one.
August 17, 2025
Loved!!!!! This is what a true psychological thriller should look like. It was so dark and twisted. I was literally on the edge of my seat the entire time. It was hard to even sleep after reading this one. It rattled me that much and that is hard to do. This authors books tends to do this to you and this is why I like them so much. They always make for one heck of read. So I don’t know where to start. How about the characters. Every character fit perfectly. Each of them had certain characteristics about them to make the story great. Next up the plot. The first sentence of the blurb is what really drew me in to this one. I just had to find out more after I read that tagline. Who wouldn’t find it interesting? This whole book was intriguing and different. When you read many books like I do you find that they are very similar to one another but not this one. It had a fresh story that kept me on my toes. I loved that. Now I want to talk about that ending. Wow, just wow. I never saw that coming not in a million years. I’m still trying to get over that one. Kudos to this author for writing such a wonderful read. I really enjoyed it and I would recommend it to everyone.
November 17, 2025
This was interesting on so many levels with a simple plot you hear a baby crying behind a locked door of someone you love and trust. The mother and baby appear to have been held hostage and your friend is not speaking. Somehow you start being involved in it all with social media and everyone have their own take as it takes over your life and your family. You have a gut feeling that something isnt quite right but nothing prepares you for the reality of it all. This hooked me especially as the truth was revealed as no-one was how they appeared to be. The real action and reveal was great the pacing was perfect it made you think it was something it was not. It felt in places the research that had been done to make this as close to real as possible was too real. One of the deaths had me question . All the characters were flawed and this story twists and turns had you reading on and one. It felt long in places but without the length i don't think i would have cared as much about anyone or wanted the reveal. This is a solid 4 star read perfect for anyone who loves to trust their eyes until their head kicks in. Thank you so much to netgallery, publsiher and author. Part of her hopes this is not the end
September 25, 2025
A pretty good thriller that I thought was going to be an unreliable narrator type - not knowing what is really going on, what others are thinking, etc - but it did narratively jump around. I'm not sure which direction would have been better. This was pretty well done.
The characters were all enjoyable and deep enough for the story. There was a pretty big, I don't want to say twist because it wasn't entirely unexpected, change in tone maybe, almost directly in the middle. I was expecting something more cult-like, but this was a little more straightforward. I did get annoyed when the one mysterious bad guy was almost revealed but the character just can't say it. It felt like it was drawing it out too much, even though that part was relatively predictable.
Good narration too. The differences in voices was subtle but recognizable.
The characters were all enjoyable and deep enough for the story. There was a pretty big, I don't want to say twist because it wasn't entirely unexpected, change in tone maybe, almost directly in the middle. I was expecting something more cult-like, but this was a little more straightforward. I did get annoyed when the one mysterious bad guy was almost revealed but the character just can't say it. It felt like it was drawing it out too much, even though that part was relatively predictable.
Good narration too. The differences in voices was subtle but recognizable.
October 14, 2025
As many twists and turns as described by the author of the country lanes leading to Beckford farm! Lucy visits a friend in doing, she hears the crying of a baby and opens a locked door from then on a relatively ordered life with her teenage son turns into chaos! People aren’t always as they seem and this book depicts that wonderfully. Family feuds personal insecurity and parental hguilt come together to make this book for me, an excellent read. The narrators were great, and I would recommend this to anyone who enjoys a combination of psychological thriller, with likable characters, for the most part, a well paced book and definitely worth a read
Displaying 1 - 30 of 473 reviews