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Good Sister, Bad Sister: A BRAND NEW twisty, psychological thriller from Jill Childs for 2026
Not yet published
Expected 11 Mar 26A BRAND-NEW heart-pounding psychological thriller from international bestseller Jill Childs, perfect for fans of Lisa Jewell, KL Slater and Freida McFadden 💫🏠😮 A hidden bond. A deadly betrayal…
When Arabella learns she was adopted, her perfect life begins to crack. A lost birth mother, an unknown twin, and rising jealousy pull her into a spiral of obsession.
Helen, starting over in a quiet Cornish town, meets Arabella by chance. Their connection is instant – two fragile women offering each other help. But when Arabella vanishes to seek support for her unravelling mind, Helen is drawn into her home, her family - and her life...
As sinister events escalate, Helen begins to doubt Arabella’s mysterious illness, her too-charming husband, and the secrets locked behind closed doors.
By the time she uncovers the truth, it may be too late.
Dark, twisty, and addictive, Good Sister, Bad Sister is a gripping psychological thriller about sisterhood, obsession, and how far we’ll go to rewrite the past.
Praise for Jill
‘Brilliant, thrilling and fiendishly addictive. The author masterfully takes us on a journey, packed with twists. A book I cannot put down and one I will be thinking about for a very long time.’ Renita D’Silva ⭐⭐⭐⭐⭐
‘A chilling, edge-of-your-seat read that will knock the life right out of you!! A must read!! Another brilliant author that keeps you entertained from the very first page!!’ Goodreads reviewer ⭐⭐⭐⭐⭐
‘Omg! I was blown away… This absolutely got under my skin… I was not able to put the book down. It literally made an hour on the treadmill feel like 3 minutes! Just perfect! I loved every second of it.’ Goodreads reviewer ⭐⭐⭐⭐⭐
‘Oh wow… once I started I could not put it down… So many twists… when you think you know how it’s going to end boom another twist… Fantastic.’ NetGalley reviewer ⭐⭐⭐⭐⭐
When Arabella learns she was adopted, her perfect life begins to crack. A lost birth mother, an unknown twin, and rising jealousy pull her into a spiral of obsession.
Helen, starting over in a quiet Cornish town, meets Arabella by chance. Their connection is instant – two fragile women offering each other help. But when Arabella vanishes to seek support for her unravelling mind, Helen is drawn into her home, her family - and her life...
As sinister events escalate, Helen begins to doubt Arabella’s mysterious illness, her too-charming husband, and the secrets locked behind closed doors.
By the time she uncovers the truth, it may be too late.
Dark, twisty, and addictive, Good Sister, Bad Sister is a gripping psychological thriller about sisterhood, obsession, and how far we’ll go to rewrite the past.
Praise for Jill
‘Brilliant, thrilling and fiendishly addictive. The author masterfully takes us on a journey, packed with twists. A book I cannot put down and one I will be thinking about for a very long time.’ Renita D’Silva ⭐⭐⭐⭐⭐
‘A chilling, edge-of-your-seat read that will knock the life right out of you!! A must read!! Another brilliant author that keeps you entertained from the very first page!!’ Goodreads reviewer ⭐⭐⭐⭐⭐
‘Omg! I was blown away… This absolutely got under my skin… I was not able to put the book down. It literally made an hour on the treadmill feel like 3 minutes! Just perfect! I loved every second of it.’ Goodreads reviewer ⭐⭐⭐⭐⭐
‘Oh wow… once I started I could not put it down… So many twists… when you think you know how it’s going to end boom another twist… Fantastic.’ NetGalley reviewer ⭐⭐⭐⭐⭐
- GenresThriller
297 pages, Kindle Edition
Expected publication March 11, 2026
26 people want to read
About the author
Jill Childs
20 books191 followersJill 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.
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.
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Displaying 1 - 10 of 10 reviews
Review of advance copy received from Netgalley
Arabella has always had an entitled upbringing. Her parents were very wealthy and she wanted for nothing, except maybe their love. In the event of her mother's death, as well as inheriting even more money, she discovers that she was adopted. When she meets her birth mother her life is thrown even more when she's told she was a twin and her birth mother had kept that daughter. Bella feels unloved all over again and this causes her life to unravell as she becomes obsessed with her sister.
Helen has never known about her twin either, and her life has been much different, but when she meets Arabella she feels as though she's known her for years.
This was a great read, I liked how the parts centred on one sister at a time rather than alternative chapters. The storyline was mysterious and kept me enthralled
Helen has never known about her twin either, and her life has been much different, but when she meets Arabella she feels as though she's known her for years.
This was a great read, I liked how the parts centred on one sister at a time rather than alternative chapters. The storyline was mysterious and kept me enthralled
Review of advance copy received from Netgalley
Thank you to Jill Childs, Boldwood Books, and NetGalley for an advanced reader copy of Good Sister, Bad Sister.
Good Sister, Bad Sister was a fun, twisty psychological thriller and my first read by Jill Childs. I really enjoyed the dual POV, which added tension and kept the mystery moving, and the premise pulled me in straight away. The book touches on interesting themes like sibling rivalry, wealth, and family dynamics, which made for a really interesting take on a domestic thriller.
That said, as someone who reads a lot of thrillers, I was able to predict several of the twists early on. I also wanted more explanation behind some of the reveals — the twists were there, but I would have loved a deeper look into the motivations behind them. Overall, a solid and entertaining read that would make a great screen adaptation.
Good Sister, Bad Sister was a fun, twisty psychological thriller and my first read by Jill Childs. I really enjoyed the dual POV, which added tension and kept the mystery moving, and the premise pulled me in straight away. The book touches on interesting themes like sibling rivalry, wealth, and family dynamics, which made for a really interesting take on a domestic thriller.
That said, as someone who reads a lot of thrillers, I was able to predict several of the twists early on. I also wanted more explanation behind some of the reveals — the twists were there, but I would have loved a deeper look into the motivations behind them. Overall, a solid and entertaining read that would make a great screen adaptation.
January 30, 2026
I couldn’t put this one down, I needed to know what happened next.
This plot was amazing, I was constantly left guessing and when I finally thought I’d figured it out there was another plot twist. I also love the way this author writes, instead of it changing POV each chapter it was done in sections, it made it a lot easier to follow.
I can’t reveal much more without spoiling the book, but overall this is a really great psychological thriller. Just be warned, if you’re easily caught up in suspense, don’t start reading late at night.
* full disclosure I was given this book in exchange for an honest review through NetGalley*
This plot was amazing, I was constantly left guessing and when I finally thought I’d figured it out there was another plot twist. I also love the way this author writes, instead of it changing POV each chapter it was done in sections, it made it a lot easier to follow.
I can’t reveal much more without spoiling the book, but overall this is a really great psychological thriller. Just be warned, if you’re easily caught up in suspense, don’t start reading late at night.
* full disclosure I was given this book in exchange for an honest review through NetGalley*
Review of advance copy received from Netgalley
Good Sister, Bad Sister by Jill Childs is a tense psychological thriller about the complicated bond between two sisters and the secrets that refuse to stay buried. The story slowly unravels past trauma and long-held resentment, keeping you guessing about who to trust.
I really enjoyed how the author focused on the emotional side of sibling rivalry and family dysfunction, not just the twists. The suspense builds steadily, and just when you think you’ve figured it out, another layer is revealed. If you like domestic thrillers with messy family dynamics and unexpected turns, this is a solid read.
I really enjoyed how the author focused on the emotional side of sibling rivalry and family dysfunction, not just the twists. The suspense builds steadily, and just when you think you’ve figured it out, another layer is revealed. If you like domestic thrillers with messy family dynamics and unexpected turns, this is a solid read.
Review of advance copy received from Netgalley
Thank you to NetGalley and Boldwood Books.
Arabella is rich, has a wonderful husband and a beautiful daughter, but when she discovers that she is adopted and has a twin sister, her insecurities cause her world to fall apart.
Helen is trying to survive when she meets Arabella and they bond instantly. Trying to help her friend in serious trouble, Helen delves into Arabella's life and begins to suspect everything and everyone.
A novel in which the characters are well defined with their imperfections and virtues and a plot that absorbs the reader and leaves no one indifferent.
Arabella is rich, has a wonderful husband and a beautiful daughter, but when she discovers that she is adopted and has a twin sister, her insecurities cause her world to fall apart.
Helen is trying to survive when she meets Arabella and they bond instantly. Trying to help her friend in serious trouble, Helen delves into Arabella's life and begins to suspect everything and everyone.
A novel in which the characters are well defined with their imperfections and virtues and a plot that absorbs the reader and leaves no one indifferent.
Review of advance copy received from Netgalley
When Arabella learns she was adopted, her perfect life begins to crack. She finds out she has a twin and everything escalates. Who is the bad sister?
This is my second book by this author, and I loved it! The mystery with the two sisters built throughout the entire book – it was hard to figure out the plot but well worth it at the end – highly recommended this one if you like psychological thrillers that keep you guessing!
It’s a gripping exploration of how well we truly know the people closest to us – and how far we might go to protect ourselves or those we love.
This is my second book by this author, and I loved it! The mystery with the two sisters built throughout the entire book – it was hard to figure out the plot but well worth it at the end – highly recommended this one if you like psychological thrillers that keep you guessing!
It’s a gripping exploration of how well we truly know the people closest to us – and how far we might go to protect ourselves or those we love.
Review of advance copy received from Netgalley
Arabella is married to Danny and they have a lovely daughter named Lola when Arabella suddenly discovers she was adopted as a child! And if that isn't enough, she also finds out that she may have a sister! Now we have two women whose lives are completely upended with news that has been kept from them for years. it's a fast-paced novel that involves violence, trickery, but most of all love! I couldn't finish this fast enough!
Thanks to NetGalley for this ARC!
Review of advance copy received from Netgalley
Arabella is adopted. She had everything a child could dream of, except the love of her mother. Her adoptive mother. Helen, her twin remained with her birth mother and was loved beyond measure.
A very well thought out plot. I enjoyed it, and had an inkling of the twist in my mind, and was right.... but there was so much more!
It is chilling, heart rending, emotional, and makes you wonder if our upbringing does shape our future selves.
A thoroughly enjoyable and enthralling read.
A very well thought out plot. I enjoyed it, and had an inkling of the twist in my mind, and was right.... but there was so much more!
It is chilling, heart rending, emotional, and makes you wonder if our upbringing does shape our future selves.
A thoroughly enjoyable and enthralling read.
Review of advance copy received from Netgalley
Review to come.
5 stars.
Thanks to Jill Childs and Boldwood Books for an eARC in exchange for an honest and. voluntary review.
5 stars.
Thanks to Jill Childs and Boldwood Books for an eARC in exchange for an honest and. voluntary review.
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February 6, 2026Thank you NetGalley and boldwood ffor the ARC
Arabella is a rich and successful woman she has everything every women dream of money beautiful sea facing house a handsome husband a lovely daughter life was good until her mother died and left her a note saying she was adopted her life crashed another twist she has a twin sister.
Well I guessed the twist and the criminal in the beginning of this book
Arabella is a rich and successful woman she has everything every women dream of money beautiful sea facing house a handsome husband a lovely daughter life was good until her mother died and left her a note saying she was adopted her life crashed another twist she has a twin sister.
Well I guessed the twist and the criminal in the beginning of this book
Displaying 1 - 10 of 10 reviews