Good Sister, Bad Sister

by Jill Childs

248 pages, Paperback

Published March 11, 2026

About the author

Jill has always loved stories - real and imaginary. She's spent 30 years travelling the world as a journalist, living overseas and reporting wherever the news took her. She's now made her home in London with her husband and twin girls who love stories as much as she does.

Although she's covered everything from earthquakes and floods, riots and wars, she's found some of the most extraordinary stories right here at home - in the secrets and lies she imagines behind closed doors on ordinary streets, just like yours.

Reviews

[Ramona Ziemele (grāmatu lāde) · Rating 4 out of 5]

3.5⭐️

This is definitely a popcorn thriller due to it being written in a very simple manner and there are no gory details.

Although it did keep my interest throughout it left a "i have read it already" feeling as it was full with scenes we all have seen on TV or in pages of other books. I was lacking surprises.

Yes, the villain of the story was not noticable at the beginning so that was a nice touch.

I would say that this one will be a good read for those who enjoy a simple writing like in Frieda McFadden books.

[Fleury · Rating 4 out of 5]

This is a really good book. I certainly enjoyed it.

It has wonderful characters, each doing something different yet are connected

I'll happily read anything else Jill Childs. I'll check out what else she has written.

I would highly recommend this book, it's very good

[Debbie Williams · Rating 4 out of 5]

My Review: Good Sister, Bad Sister by Jill Childs
Rating: ⭐⭐⭐⭐ (4/5 Stars)
I’ve always been a sucker for a "shattered perfection" story, and Jill Childs really delivered with this one. Good Sister, Bad Sister is a tense, atmospheric psychological thriller that kept me guessing—and honestly, feeling a little paranoid—until the very end.
The Plot: A Slow-Burn Obsession
The story follows Arabella, a woman whose "perfect" life is upended by the discovery that she was adopted and has a twin sister out there somewhere. This discovery sends her into a psychological spiral that felt incredibly raw and well-written. Enter Helen, who is trying to escape her own past in Cornwall. When their paths cross, I was immediately hooked by their "instant" connection.
What I loved most was the blurring of lines. As Helen gets pulled deeper into Arabella’s family and home, the boundaries between help and intrusion start to vanish. I found myself constantly questioning who was actually the "good" one and who was the "bad" one.
What Worked for Me
• The Setting: The Cornish backdrop added a layer of isolation that worked perfectly for the rising tension.
• The Suspense: It isn’t just about the mystery of the missing sister; it’s about the husband, the secrets in the house, and Arabella’s fading grip on reality.
• The "Twisty" Nature: Just when I thought I had figured out the dynamic, Childs would drop a hint that made me doubt everything.
Final Thoughts
While there were moments where I wanted to shake the characters for their choices, the sense of dread kept me turning the pages. It’s a solid, dark exploration of identity and how far someone will go to reclaim a life they think they deserve.
If you like thrillers that focus on domestic suspense and the dark side of family bonds, I’d definitely recommend picking this one up!

[Leanne · Rating 4 out of 5]

Good Sister, Bad Sister is one of those psychological thrillers that quietly hooks you from page one and then refuses to let go. Jill Childs blends family secrets, emotional tension, and slow‑burn suspense into a story that feels both intimate and unsettling in all the right ways.

Arabella’s seemingly perfect world begins to crumble the moment she discovers she was adopted — and that revelation opens the door to one twist after another. Her spiralling jealousy, her obsession with uncovering the truth, and the eerie sense that something isn’t quite right in her life create a deliciously uneasy atmosphere throughout.

Then comes Helen — gentle, lonely, trying to rebuild her life on the Cornish coast — who stumbles into Arabella’s orbit at exactly the wrong (or maybe the right?) moment. Their fragile connection is beautifully written, and as their lives intertwine, the tension slowly ramps up in a way that made me question every character’s motives.

Childs does a brilliant job of blurring the line between pity, fear, and suspicion. The more Helen steps into Arabella’s world, the more the story takes on that classic psychological‑thriller claustrophobia: the charming husband who feels a little too charming, the illnesses that don’t quite add up, and the creeping dread that something terrible is lurking just out of sight.
By the time the truth comes out, the pieces click together in a way that’s both satisfying and haunting.

A dark, twisty, character‑driven thriller about sisterhood, identity, and the danger of letting strangers inside your life — and your mind. Perfect for fans of Lisa Jewell, KL Slater, and Freida McFadden.

with thanks to Jill Childs, the publisher and netgalley for the ARC

[Yvonne · Rating 5 out of 5]

WOW! This is a brilliant book; it kept me up until 1 am because I really could not put it down. It also helps that it is 258 pages, so it's relatively short; otherwise, I would have been awake even later.

Arabella lost her father a few years ago, and her mother has recently died. She left her daughter a letter which puts Arabella's life into perspective, but also twists it all ways and then some. This, however, is not just a story about her.

Helen has just recently lost her mum, and an unexpected meeting with Arabella brings them closer together, and they form a friendship. Unexpected for Helen, but not so for Arabella.

Arabella learned through her mother's letter that she had been adopted, the name of her birth mother is given, and a meeting between them takes place. It is then that she learns she has a sister, Helen, who is completely oblivious to this.

The story is one that is actually quite complex, but it wasn't during the reading. It is only now, as I sit here to type this, that I realise just how twisted and devious the author was in writing this. The sisters' lives are the polar opposite. Helen was brought up by her single mum, whereas Arabella was born into wealth. But where one had money, the other had love.

The author turns both girls' lives upside down and inside out as she weaves a story of lies, deception and betrayal. Many shocks and unexpected developments are revealed through each of the sisters' accounts.

It was so addictive, and it is such a great book to read. This is one for fans of thrillers, family and relationships, and understanding how people work and think. Fabulous story that I would definitely recommend.

[P.J. · Rating 4 out of 5]

Arabella's life appears perfect: she's incredibly wealthy and has a sweet daughter with her consultant husband, Danny. After her mother's death, she is given a letter from her that tells her she isn't her parents' biological child. To her, this explains why she always felt like she didn't belong in the home where she was raised and felt unloved. When she meets her biological mother, she also learns that she is a twin. Her twin, Helen, grew up with a lot of love but not a lot of money. She works in a boutique, barely managing her incredible debt, and lives alone. When the two meet, they have an almost instant connection despite their opposing lifestyles. When Arabella goes away to deal with her health issues, Helen agrees to care for her daughter and finds herself easily taking over Arabella's place. But she also feels the strange things Arabella had complained about in the house.

The story is told from both Arabella's and Helen's POVs. You switch POVs in a way that you aren't getting the full story and have to speculate what is causing the mysterious happenings in the house. And you aren't sure which sister is the "good" one and which is the "bad." What I liked is that you are just working with speculation until the last POV and, while things are weird and sometimes a bit creepy, I didn't feel real danger until that point. It is intriguing, but not as stress inducing as some other psychological thrillers I've read, making it seem more like something that could actually happen.

Thanks to NetGalley, Boldwood Books, and Jill Childs for the ARC in exchange for my honest review.

[Christine Antosca · Rating 5 out of 5]

This psychological thriller kept me hooked from beginning to end. The story begins when Arabella’s life is turned upside down after the death of her mother. While sorting through her mother’s belongings, she discovers a letter revealing that she was adopted. Curious and searching for answers, Arabella tracks down her birth mother and makes a shocking discovery: she has a twin sister, Helen, who was raised by the woman who gave Arabella up.

What follows is a tense and unsettling story filled with secrets, jealousy, and shifting trust between the sisters. When Arabella leaves for a spa clinic and Helen comes to stay at the house, strange events begin to occur, creating an eerie atmosphere that keeps the tension building.

One of the strongest parts of the book for me was the way the author created suspense through the mysterious happenings around the house. These moments made the story feel increasingly unsettling and kept me wondering who was responsible.

The biggest surprise was the twist involving Danny. I genuinely didn’t see it coming, and once the truth was revealed, many earlier moments in the story suddenly made sense.

What I appreciated most was how the novel explored the idea of the “good sister” versus the “bad sister.” By the end, it becomes clear that neither Helen nor Arabella fits neatly into either category. Both characters are flawed and shaped by the secrets surrounding their family.

Overall, this was a gripping psychological thriller with strong tension, an unexpected twist, and a satisfying conclusion.

[Lauren Sasse · Rating 4 out of 5]

Good Sister, Bad Sister by Jill Childs is one of those twisty, psychological reads that keeps you questioning everything—and everyone.

From the start, there’s an undercurrent of tension that never really lets up. The story dives deep into family dynamics, secrets, and the complicated bond between sisters, and it does it in a way that feels both unsettling and completely addictive. Just when you think you’ve figured out who to trust… you realize you probably shouldn’t trust anyone at all.

The pacing is strong, with plenty of reveals sprinkled throughout to keep you hooked. I especially loved how the author slowly peeled back layers of the past, showing how everything connects in ways you don’t fully see coming. It’s one of those books where the truth is constantly shifting, and you’re left second-guessing every character’s motives.

The characters themselves were intriguing—flawed, messy, and very human. You may not always like them, but you’ll definitely be invested in what happens to them.

I’m giving it 4 stars instead of 5 because there were a couple of moments that felt a bit predictable, and I wanted just a little more depth in certain emotional reveals. Still, it didn’t take away from how gripping the overall story was.

If you love psychological thrillers filled with family secrets, unreliable characters, and plenty of twists, Good Sister, Bad Sister is definitely one to pick up.

[Zara Dal · Rating 4 out of 5]

I really enjoyed the premise of Good Sister, Bad Sister. It hooked me right from the start.

The story begins with Arabella, who, following the death of the woman she believed to be her mother, is handed a letter revealing that she was actually adopted. The parents she had known all her life were not her biological family, and the revelation sends her searching for the truth about where she really came from.

When Arabella tracks down her biological mother, she discovers something even more shocking — she has a twin sister, Helen.

From that moment on, the story really begins to pick up pace. The sisters meet and slowly begin weaving themselves into each other’s lives. On the surface, Arabella appears to have everything together, but Helen can’t help feeling that there might be something darker lurking beneath her sister’s seemingly perfect exterior.

This is a tense and twisty thriller, but it also carries an emotional core as both sisters struggle to come to terms with the secrets and lies that kept them apart for so many years.

The story gripped me from the beginning and I found it hard to put down. I had a couple of theories about where the plot might go, but I wasn’t disappointed at all by the direction it took. The ending and final showdown were incredibly satisfying and made for a strong finish.

[Stephanie Bull · Rating 3 out of 5]

Good Sister, Bad Sister centres on two sisters whose lives are connected by deeply buried secrets. Very close to her mother, Helen has recently moved back to the area she grew up in. Struggling financially she works hard to make ends meet. Arabella, the only child of extremely wealthy parents, has wanted for nothing. They meet by chance however their connection is instantaneous.

I enjoyed the book enough to pick it up at every opportunity because I did want to know what happened. However, for me, the storyline felt quite predictable with minimal surprises along the way. The deliberate misdirection didn't quite work for me, and at times felt implausible. As such, it wasn't too difficult to work out where the plot was heading.

A definite plus point are the evocative descriptions of the landscape surrounding Arabella's property. The author paints the setting vividly and it adds a strong sense of atmosphere to the story.

An engaging enough read that kept me turning the pages, but the predictability prevented it from being truly gripping. Rated 3.5 stars, however rounded down as I couldn't justify the round up.

Thank you to NetGalley and Boldwood Books for my advanced reader copy in return for my honest and unbiased review.

[Jackie · Rating 4 out of 5]

3.5 ⭐️

I love discovering new authors through ARCs, and this one ended up being an entertaining, easy entry into Jill Childs’ work. This was my first time reading her, and overall it was a solid psychological thriller that kept me engaged without feeling over the top. The narrative was entertaining in a quieter way, more of a steady unraveling than a nonstop shock fest.

I’ve read a couple psychological thrillers with a similar trope before, but the engaging narrative and Childs’ writing style really pulled me in. Even without huge jaw-dropping twists, I found this to be a compelling and entertaining read that held my attention from start to finish. I liked the sister dynamic and the gradual uncovering of secrets, and the writing felt smooth and accessible, making it a quick, comfortable read when I wanted something suspenseful but not too heavy.

Since this was my first book by Childs, a big thank you to Boldwood Books and Net Galley for the ARC in exchange for my honest feedback, and I’d definitely be interested in reading more from her in the future.

[Jen · Rating 4 out of 5]

I thought this was a good book. It centers on Arabella, who realizes she was adopted after the death of the only mother she has known; and Helen, her biological twin sister who has no idea any of this is even happening. When Arabella and Helen cross paths, it’s not entirely clear who has good intentions and who has other things in mind.

The POVs shift between the two women and it was sometimes hard to figure out who was hiding potentially dark intent. The story moved at a fast clip and contained good twists overall. I was a little surprised that one of the biggest twists didn’t seem to require a lot of proof to substantiate, but overall I liked the way the story came together. I thought the ending was perfectly aligned with the rest of the book, and found it satisfying.

Overall, this was a fun and quick read that I’d recommend to those who like psychological thrillers. Thanks to NetGalley for providing me with a copy of this book in exchange for an honest review.

[Lauren Kelly · Rating 3 out of 5]

My Rating is 3.5 ⭐️’s but you can’t do half stars on here.

I slogged through Good Sister, Bad Sister because I was promised family secrets and obsession and it mostly delivered déjà vu. Arabella’s discovery should detonate her life instead it fizzles into a familiar slow burn of secrets we’ve all met before. Way too much of the middle plays like recycled beats from every domestic thriller starter pack with pacing that forgets to sharpen the knives. Helen briefly glows as a tether, but the book rarely follows through when the stakes should actually hurt. When the danger shows up, it hits okay, but those moments are too rare and too polite. I guess I expected more teeth and ended up getting polite nibbling instead. If you want edge of your seat, nail biting suspense or a villain who makes you uncomfortable in the best way, this is hard pass. But if you need a blandly emotional, light twisty read that won’t require risk this is the one for you.

[Sherry Rosen · Rating 3 out of 5]

Good Sister, Bad Sister is a story of twins separated at birth, growing up in vastly different worlds, with no knowledge of the existence of the other. When adult Arabella finds out she is adopted and has a twin sister, Helen, her life begins to unravel.

This started out strong, albeit a slow burn. It was well written and I was enthralled. It kept my attention and I read it quickly.

Sadly, the story really didn't seem to go anywhere. It didn't really have much of a "thriller" effect, although I did not expect the twist toward the end. The ending itself was abrupt and a bit lackluster; it left me wanting more. The story had potential, but with a few exceptions, I found it one dimensional.

Thank you to NetGalley and Boldwood Books for the opportunity to read this advance copy. All opinions are my own.

[Karen Knight · Rating 4 out of 5]

This tells the tale of twins Arabella and Helen, who were separated at birth and were unaware of the other’s existence. Arabella is very rich and loses the person she thought was her mother finds a letter explaining she is adopted. She manages to track her birth mother down and meets her and she lets slip she has a twin. Then her mother dies, so she sets about making friends with her twin but does not tell her who she is and they form a friendship. Helen stayed with her birth mother but does not have Arabella’s money and never knew about her twin.

Arabella’s supposedly perfect life of husband, money and daughter is not as perfect as it seems, she suspects her husband is having an affair, she seems to be drinking heavily and is a mess so Helen helps her out but are things as they seem and will she find out the truth of their blood relationship, before anything serious happens?

Initially the book reminded me of the story of Blood Brothers but it soon turned into something more psychological and kept you guessing to the end.

Thank you to the publishers and NetGalley for my advance copy of this book.

[Victoria · Rating 4 out of 5]

Title: Good Sister, Bad Sister
Author: Jill Childs
Rating: 🌟🌟🌟🌟
Publication Date: March 11, 2026

As an adult, imagine finding out you were adopted and on top of that, you also have a twin sister. Talk about shocking! The storyline was definitely intriguing. The writing style was easy and free-flowing, which I appreciated.

I have to admit, I pretty much had the whole thing figured out within the first 25% of the book. BUT, that didn't stop me from finishing the book. I found myself invested in the characters, especially Lola. I actually found myself reading this book whenever I found a spare second.

Thank you to NetGalley for the opportunity to read this ARC in exchange for my honest opinion/review.

[Tiffany · Rating 4 out of 5]

Good Sister, Bad Sister was a dark, twisty read. This is one that is more psychological, something is brewing beneath the surface type of book, as opposed to in your face murder and mayhem. The chapters are short and it flips between POV's so you get to see things from both Arabella's and Helen's perspective. It leaves you wondering if things are really as they seem. I started to have an inkling about what was going on but that definitely didn't detract from my enjoyment of this one...definitely worth reading!

Thanks to Netgalley and the publisher for the advanced copy. All opinions expressed are my own.

[Hasina Begum · Rating 4 out of 5]

Good Sister, Bad Sister by Jill Childs is a gripping psychological thriller that had me hooked from the start. While it’s a slow burn, the pacing works perfectly to build the tension.

The story follows Arabella, who discovers she was adopted only after the woman she thought was her mother passes away. When she tracks down her birth mother, she uncovers a devastating secret: she is a twin, and her mother chose to keep her sister while giving Arabella away.

This revelation sends Arabella into a spiral that is both fascinating and chilling to watch. I thought I had the ending all figured out, but I was pleasantly surprised to be proven wrong! A clever, unpredictable read.

[Maja · Rating 5 out of 5]

First things first, thank you Netgalley and also Boldwood Books for this ARC!

I am not sure why, but I do like stories about twins being seperated since watching The Parent Trap when I was little. But, different from the movie, the story in the book by Jill Childs quickly takes a way darker turn. Those two sisters only meet when they are both adults. One, Arabella, is spiraling badly because of it. And the other, Helen, does want exactly that - the perfect life her long-lost sister seems to have.... I also thought at a point I managed to figure everything out. Well, I did not and this is why I can very much recommend this book!

[Vanessa · Rating 5 out of 5]

Good Sister, Bad Sister by Jill Childs was another excellent psychological thriller that was full of brilliant twists and turns throughout that will have you turning the pages over on your kindle to find out what happens next. This was a book that was excellent from the very beginning and I wizzed throughout it as it was so good, especially as it will keep you guessing nearly till the end!

I highly recommend this book But I would not recommend you start reading Good Sister, Bad sister late in the afternoon as I ended up reading it till the early hours of the morning until I had finished!!!

Big Thank you to NetGalley and Boldwood Books for my ARC.

[Sara · Rating 5 out of 5]

Two sisters grew up in different worlds, never knowing of the other’s existence. Arabella grew up in a world of luxury and wealth but little love. Helen grew up poor but in a house of love. After her mother dies, Arabella learns she was adopted. What follows is a fast paced, heart stopping thriller! This one was hard to put down! Lots of twists and turns in this one as the lives of Arabella and Helen intertwine.

Thanks to NetGalley and Boldwood Books for the opportunity to read this great ARC! This is the first I’ve read from Jill Childs but won’t be the last!

[Roo · Rating 5 out of 5]

This was brilliant. A one sit read psychological nail biting thriller about two sisters. Arabella is a successful woman with a child Lola and husband Danny. Helen works in a shop and is in debt and when she loses her job, she picks up work looking after Lola. Then the plot thickens and the truth and lies emerge. I liked the way this book is written so you get both of the sister’s perspective. It’s a jaw dropping read and worth 5 stars. A gripping tangled web of lies. Thanks to Netgalley and the publishers for a copy.

[Jerelyn · Rating 4 out of 5]

This was a fun twisty read! Arabella discovers that she was adopted, challenging her vision of a picture-perfect life. Helen meets Arabella by chance, and the two of them find that they have more in common than just offering support to each other. Helen is suspicious of everything: Arabella's sudden illness, her too kind husband, and every secret found behind her home's perfectly locked doors.
Good Sister, Bad Sister kept me entertained and questioning what was happening in each chapter! I enjoyed trying to solve the twists as I read.

[Victoria Ann · Rating 4 out of 5]

I LOVE a psychological thriller and this book does not disappoint! I like the dual perspective and felt it worked well… at no point was I left confused.

The book is easy to read and can easily be finished in a single sitting which I like. Perfect for getting out of a slump!

It’s hard to put yourself in Arabella’s shoes but her story keeps you hooked. Waking up one day to find out your life is a complete lie and that not only are you adopted… but you have a twin too! Just wow.

[Mindy · Rating 4 out of 5]

Arabella lives a perfect life. But, when her mother passes, she learns she is adopted. The huge secret changes the way she thinks of her entire life. She befriends her twin sister, Helen, who grew up the complete opposite of Arabella.

Which one is the “good sister”? Who is the “bad sister”? This psychological thriller grabs hold of you at the very start and never lets go.

Thank you Jill Child and Boldwood Books for the gifted copy of this book.

[Jennifer · Rating 5 out of 5]

Good Sister, Bad Sister by Jill Childs is a twisted mystery that creates a creepy and unsettling atmosphere. The author skillfully builds suspense and employs clever tricks to keep me engaged in the story. I couldn’t help but wonder what was happening with these women and whether anyone was telling the truth. The novel left me questioning both sisters’ motives and actions. Overall, I thoroughly enjoyed it and loved the ending.

Thanks, Boldwood Books via NetGalley.

[Carmen DaVinleam · Rating 5 out of 5]

This book pulled you in and hooked you pretty quick. It makes you question... can family be found family, too, and if they are... is it safe?
This book was well written and kept a good pace. If you like psychological thrillers you'll enjoy this read.
And that ending! *mouth drop* while reading for sure!

[Akeating2003 · Rating 3 out of 5]

3.5 stars. I was afraid that this type of scenario has been done before (one rich, unloved, superficial sister and one much-loved, caring sister) but the story had some good twists. Both characters had a lot of background to help understand why they went the way they did. The middle part is kind of absurd, but it's a good quick read.

Thank you to NetGalley for the ARC!

[Claire · Rating 5 out of 5]

Wow! I loved this book. It’s only short, less than 300 pages, but it packs a lot in. It’s a fast paced thriller, with a brilliant plot that unfolds with ease. It gets its hooks into you from the start and you are compelled to keep turning the pages to the end. It’s an addictive thriller that I highly recommend. Thank you to NetGalley, Boldwood Books and the author for the chance to review.

[Merkie · Rating 3 out of 5]

Good Sister, Bad Sister was a fun, fast read. While the story is distinctly different, I got Verity vibes. I think that if you enjoy Colleen Hoover thrillers or Freida McFadden you would enjoy this. There are a lot of twists and turns but they do lean a little predictable. I had fun reading this.
Thank you to NetGalley and the publisher for this ARC in exchange for my honest opinion.