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The Mistake

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Two sisters. One mistake. A thousand consequences.

Kate and Bec are sisters, but they could not be less alike.

Bec lives the perfect life: perfect house, perfect husband, perfect children. That is, until she meets Ryan - ten years her junior, wild and exciting, his arrival makes her question everything she thought she wanted.

Her sister Kate's life is anything but perfect. Her career as a model ended dramatically over a decade ago; now she lives alone miles from her family, and has been lonely for a long time. That is, until she meets kind, funny Adam. But something doesn't quite add up, and as he avoids Kate's questions, she begins to wonder if he is too good to be true.

Bec thinks Adam is only after her sister's money, and Kate can't see why Bec would throw her life away for Ryan.

But as tensions mount and secrets are revealed, which sister is about to make a mistake?

A novel about mistakes and choices, relationships and forgiveness, The Mistake will have you turning pages long into the night. Not since Liane Moriarty and Marian Keyes have we met such sharp, sassy characters and been captivated by such a suspenseful, tantalising read.

310 pages, Kindle Edition

First published April 29, 2021

400 people are currently reading
1150 people want to read

About the author

Katie McMahon

4 books72 followers

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5 stars
693 (27%)
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972 (39%)
3 stars
595 (24%)
2 stars
157 (6%)
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62 (2%)
Displaying 1 - 30 of 178 reviews
Profile Image for Gloria (Ms. G's Bookshelf).
912 reviews195 followers
July 24, 2021
⭐️4 Stars⭐️
Deliciously entertaining!

The Mistake is a well written, edgy and impressive debut by Australian author Katie McMahon.

There’s a simmering silence between two sisters that’s changed the course of their lives. Kate and Bec have a very close sibling relationship although they live in different states. They chat frequently and are always there for one another.

Kate lives in Melbourne and was a successful model until life dealt her a hard blow and her career ended suddenly. She’s vulnerable and has never found anyone special to share her life but then she meets Adam …. can she trust him?

Bec is living in Hobart and married to a surgeon, they have three children and live the ideal life or so it seems until she meets Ryan, a much younger man. Will she risk everything for her attraction to him?

This is a journey of two very different and wealthy sisters, their bad decisions, choices and relationships.

The characters in the book are likeable and the storyline unpredictable, it was a page turner for me!

The Mistake is outstanding and is certainly a story that will hold your interest from start to finish. If you love suspense, thrillers, domestic dramas, romance, wit and heart this is for you.

I cannot wait to see what Katie McMahon writes next!

Publication Date 29 April 2021
Profile Image for Veronica ⭐️.
1,332 reviews290 followers
April 20, 2021
4.5 stars
The Mistake is an outstanding and impressive debut by Australian author Katie McMahon.

Kate was a successful model working around the world when her career ended suddenly. She now pursues an academic career. Her younger sister Bec, a doctor's wife, lives the perfect life; a handsome husband, a beautiful house and three gorgeous children. Everything Kate aspires to.

There is something between the sisters, simmering menacingly, something that's never been discussed but changed the course of both their lives irrevocably.
The dual narrative gives the reader a greater sense of the sisters' relationship and how each of them feels. With Kate's in first person I found her character more open and vulnerable, than the third person narrative of Bec. 

As Katie's life finally starts to be looking up in the romance department Bec's life and marriage are falling apart. When Bec starts to get attention from the much younger Ryan she can't resist the urge to break free. Kate and Bec will always be there for each other and tell each other everything. Or do they? Katie McMahon explores the bond between sisters, beauty, sexuality and fidelity.

I had a small idea of what was going on but I had no idea where McMahon was taking this and found this shrewdly plotted novel both believable and well executed. 

McMahon gives the reader a deep insight into the sisters innermost thoughts, fears and the events that bind them together and tear them apart. Delivered in two intertwining plot lines The Mistake held my interest from start to finish.

In this genre defying novel McMahon mixes family drama with romance, suspense, humour and satire. Her writing is sharp, succinct and delivered with a wry wit.

The Mistake is honest, heartfelt and engaging. I'm looking forward to more from Katie McMahon.
*I received a copy from the publisher
Profile Image for Mandy White (mandylovestoread).
2,784 reviews852 followers
February 28, 2021
The Mistake is a fantastic debut novel from Australian author Katie McMahon.

A story of 2 sisters who couldn't be more different and the mistakes that change their lives. Bec lives in Tasmania with her surgeon husband and their 2 kids. She has the perfect life. So why would she risk it on the younger man Ryan who she meets at her husbands birthday party of all places? Kate is an ex-model who lives in Melbourne alone. Then she meets Adam. He is just what she needs but something doesn't seem right.

This book made me laugh and it made me emotional. What happens when one decision leads to a whole load of trouble and change. Relationships of all kinds are tested and choices need to be made.

Thanks to Allen and Unwin/Echo Publishing for my advanced copy of this book to read.
Profile Image for Amanda - Mrs B's Book Reviews.
2,234 reviews332 followers
March 30, 2021
*https://mrsbbookreviews.wordpress.com

The Mistake is the sensational debut from a fresh new voice in Australian contemporary fiction, Katie McMahon. A story of sisterhood, secrets, the past, relationships, choices and personal struggles, The Mistake is an illuminating read that I found really entertaining.

The Mistake provides an imitate portrait of the lives of two very different sisters, Bec and Kate. While Bec lives quite the privileged existence as a doctor’s wife, with her perfect home and family, she still longs for some excitement in her life. Is she willing to risk it all for a dalliance? On the other hand, Bec’s sister Kate has been single for years, choosing to dedicate her life to academic work. However, Kate is tempted to enter into a relationship with Adam, a man with charms she cannot resist. But Adam is hiding something from Kate. What will Kate do when she discovers his secrets? This debut offering by Katie McMahon takes a penetrating look at right versus wrong and the impact of personal errors.

The Mistake was written by author Katie McMahon after she attended one of bestselling author Fiona McIntosh’s highly regarded writing masterclass courses. I have enjoyed the books of a number of other authors who have graduated from this class, so I was naturally very interested in The Mistake. With a glowing front cover endorsement from Liane Moriarty, I was super keen to read this one. There were no regrets attached to picking up The Mistake, it was a riveting read!

I continue to be fascinated by sister based dynamics and I think this can be attributed to my own family circumstances growing up with only a younger brother and no sisters. It was interesting to see such vastly different siblings in this novel. McMahon has a clear understanding of the intricate relations between sisters and she is also able to examine their separate identities. Within the pages of The Mistake we as the reader are presented with two polar opposite individuals in terms of thoughts, feelings, actions and life situations, but the family connection is still there. Through the use of a shifting first-person style narrative, we are privy to the inner mindset and emotions of both sisters. I enjoyed the company of both these women for the duration of the novel.

The Mistake is a sort of hybrid style novel that pulls in genres such as women’s fiction, romance, suspense and psychological elements to direct the narrative. Themes of family, marriage, sibling relationships, parenting, careers, trust, the past, trauma, health crisis, infidelity, trust and identity are prevalent. Many of these thought-provoking themes throw up some revealing moments and interesting situations for the characters in The Mistake to contend with. I am sure Katie McMahon’s novel would work well with book clubs as there is plenty to discuss due to the issues raised.

Overall, I connected to this novel. I liked the characters, the storyline was intriguing and unpredictable. The pace is even and McMahon works hard to build the tension level throughout. I thought it was all closed off in a believable manner. Please do take a chance on this debut author and her first novel, The Mistake is an edgy read that I would happily pass onto others to enjoy.


*Thanks extended to Echo Publishing for providing a free copy of this book for review purposes.

The Mistake is book #25 of the 2021 Australian Women Writers Challenge
172 reviews2 followers
August 22, 2021
I saw this book in a local bookshop and the summary interested me. I started to read it and all I could think was it was a mistake to read it. I couldn't stand either Bec or Kate. I found the story long and boring and I almost DNF it. I found the last 100 pages were the most interesting but I wouldn't recommend this book as I think there are much better books out there.
Profile Image for Tish.
166 reviews1 follower
August 5, 2021
Ok. I think the last 100 pages were a lot better then the first nearly 300 odd
Profile Image for Mellisa.
589 reviews154 followers
August 26, 2021
Kate and Bec are sisters but complete opposites. Bec has the perfect life, perfect husband, perfect children. Kate modelling career ended suddenly over a decade before, she's lonely and struggling to connect with people. Then, Kate meets Adam, who seems a dread come true. However, the little lies and avoiding questions aren't adding up for Kate - she's wondering how much she can really trust him. Bec has met exciting Ryan, who's changed her life and given her something she hadn't realised was missing - but is there something behind this mysterious Ryan?

Secrets, tension, betrayal. This book has it all, it's a fantastic story from start to finish, with a very good ending that completely ties up the book.
Profile Image for Craig and Phil.
2,234 reviews134 followers
May 8, 2021
A contemporary fiction story with flecks of domestic drama and the mistake that changes everything.
Kate and Bec are complete opposites and sisters.
Bec is married to a successful surgeon and has three children living the perfect life in Tasmania but something is missing.
Kate is dating and used to be a model until a tragedy changed that, she then meets Adam, a man too good too be true until she finds out he’s keeping secrets from her.
Then The Mistake happens and their lives are never the same again.
A new talent in a genre that’s fast becoming one of this country’s most popular.
While attending Fiona McIntosh’s writing masterclass, Katie came up with an idea that turned out to be this book and what a spellbinding read it is.
I was very keen to pick this up and I was totally engrossed from the word go.
There’s much to appreciate here, with a character driven plot that held my interest all the way through, wonderfully written and a storyline that’s not only intriguing but entertaining as well with a few twists along the way.
Katie delves deep into the complexities and personal relationships of sisters and how women treat each other.
Humour, vulnerability, tension, fears and of course lots of drama are some of the threads that take this story to the next level.
As I’ve said before, there’s something enticing about reading about sisters and ones that are complex, damaged and wicked make it even more irresistible.
Her writing is intelligent, captivating, smart and passionate.
Katie weaves a compelling and interesting tale.
Profile Image for Natalie M.
1,437 reviews91 followers
July 19, 2021
An outstanding debut novel by Australian author Katie McMahon.

'The Mistake' (or mistakes - multiple) is an impressive contemporary read which features sisters Kate and Bec. I really liked the authentic and genuine relationship between the sisters, their fallibility and their search for answers to the multitude of dilemmas that life throws their way.

I really enjoyed the slow reveal of Kate's issues. She was on a path to success as an international model working when her career ended suddenly. Back in Melbourne, Australia, she is working as an academic. Her younger sister Bec, a doctor herself, is married to a reputable surgeon. She is living what seems to be the perfect life in Hobart, Tasmania. An attractive, well-liked husband, a seaside dream home and three beautiful children. Kate's life finally seems to be coming together, just as Bec's marriage begins to fall apart. Of course, there is a very delectable fire-eating Byron Bay surfer, Ryan - who could resist!

There is so much left unsaid between the sisters, and inevitably this forms the backdrop to the irrevocable twists life both throws at them and the life they choose. Told from each sister's POV, it is easy to become deeply invested in their choices.

I did not see the twist! I had no idea where McMahon was going to go with this, but it was both cleverly constructed and, by that stage, entirely believable. It was far more suspenseful than I was anticipating - family drama, humour, life!

Definitely, an author to add to my list! The intertwining plot lines and characters really made this a satisfying read.
Profile Image for Nicki.
2,164 reviews15 followers
April 12, 2023
Way too mum lit for my tastes, but an easy read and I was interested to find out what The Mistake was. Some good twists, but lost half a star for use of my least favorite trope on the final page.
Profile Image for Seadaz.
488 reviews3 followers
April 29, 2021
Sorry I didn’t enjoy this, nearly DTF. I didn’t take to either of the sister characters or to Stuart - all so self indulged, smug and arrogant - and just not nice, Adam was ok but even he had doubt thrown at him as to his character, was he a photographer or after Kate’s $.

Bec and Stuart are married with two daughters and one son. Both are drs, Bec no longer practising and is a stay at home mum, while Stuart is a popular surgeon. Kate is Bec’s sister and was a model in her younger years. Bec’s family is rocked when Stuart is accused of making an inappropriate sexual request of a minor. Bec turns to a much younger man.

But all is not how it appears, and does Kate have resentment of Bec for advice given years ago, and is Bec jealous of Kate’s hedonistic lifestyle?

One pet peeve of mine is the numerous (bracketed information) and the excessive use of ! In a story. This writing was full of my pet peeve.

The story jumped all over the place, and only got interesting once Adam and Kate worked out what was happening, last few chapters.

Oh and when did a lap dance suddenly change to a lap band (page 356).

And lastly, I don’t think I’ve read such a long drawn out Epilogue before.

I know this is this author’s first published book, and I think the plot was a good idea, but for me not executed well. I do also realise that most of the reviews for this book seem to be highly flattering, so it probably means this book was just not for me, and most would enjoy it.
58 reviews
May 25, 2021
Really tedious- I gave up about 1/4 of the way through- sometimes I wonder if I am reading the same book as everyone else...............
Profile Image for Janine.
730 reviews61 followers
April 13, 2021
Oh my what a great book this one was. The story of two sisters, Bec happily married to Stuart who is a prestigious surgeon and Kate who had a top career as a model until an illness ended that career.

The title The Mistake is intriguing as there are several mistakes that occur in the plot during this book! Bec's world comes tumbling down when her husband is accused of being inappropriate and is relieved of his rights which means that their privileged life is no more. The consequences of this to their marriage sees one of them stray from their vows. Kate has been alone since her illness and when she finally meets Adam she is overjoyed - but is he what he appears to be?

This book had me hooked from the beginning and its hard to believe that this is a debut novel by a new voice in Women's Fiction. The writing was so engaging and had me turning pages into the wee hours of the morning to get it finished as I couldn't put it down. An excellent example of womens fiction which readers who enjoy female friendships, sibling relationships, intrigue, romance and a mystery will devour this book. So excited to see what the future holds for Katie McMahon - looking forward to her next book!
231 reviews6 followers
July 9, 2021
Have you ever made a mistake you lived to regret?

Sisters, Bec and Kate certainly have!

Bec is wife to a reputable surgeon, happily married with three children so why can't she stop thinking about Ryan?

When Bec's husband, Stuart is accused of inappropriate behaviour and suspended from practicing without pay their prestigious lifestyle soon goes by the wayside.

Will the effects of this accusation and lifestyle change be enough for Bec to make the mistake of falling into the arms of a free-spirited younger man?

Kate is single, previously a successful up and coming model until 'the incident' changed her life forever! Kate hasn't dated in 10 years but then she meets Adam.... he is so lovely but all is not what it seems!

What is Adam hiding? Could Kate have just made a mistake in taking the risk to date again?

An enjoyable domestic suspense with added touches of romance and humour that starts out as a slow burn but ramps up as the story goes on and is wrapped up nicely like a bow at the end!

I look forward to reading more from this author in the future.

Thank you to Echo Publishing for this #gifted copy in exchange for my honest review.
Profile Image for Sarah Clutton.
Author 4 books83 followers
February 25, 2021
It is mind blowing and actually quite unbelievable that this utterly brilliant novel is a debut. With excoriating wit, penetrating insight and tender good humour Katie McMahon has written an absolute gem. Layered, realistic, gut-laughingly funny and just plain page-turnery, it is part love story, part sexy women’s fiction, part domestic/psychological suspense and, well, really just entirely its own thing. Katie McMahon dissects human interactions with the eye of a scientist then serves up the pieces with a side of humour and a dash of sass. All I can say is that ‘The Mistake’ is a truly wonderful. If you like Sally Hepworth, Marion Keyes or Liane Moriarty (who clearly loved this book too since there is a pretty pink sticker with her endorsement on the front cover) you are bound to adore it. I have been waiting for a startling new fiction voice like this for years and I cannot wait to see what Katie McMahon writes next! Thank you to Echo Publishing for the ARC. I cannot recommend this book highly enough!
Profile Image for Rachael Young.
42 reviews2 followers
April 25, 2021
Well written and easy to read. I just couldn’t get into it. I found there were so many hints to certain things it just annoyed me. I also thought the story kind of dragged on a bit - even the epilogue to be honest. It definitely wasn’t a page turner for me and I skimmed a lot. While reading a lot of the events that happened felt really mundane - of course I know now a lot of these events were needed to bring the whole book, and the ending, together. I enjoyed the last quarter of the book a lot more than the rest - especially because the chapters became shorter. Not sure if I would recommend. So many mixed feelings about this book!
Profile Image for Amy.
153 reviews2 followers
August 24, 2021
Intriguing story and kept me interested throughout.
Profile Image for Jasmine.
114 reviews3 followers
January 29, 2025
2.5 rounded up. Nothing happened until 87% in and then it was all happy endings for everyone. Not my cup of tea.
Profile Image for Kylie.
1,600 reviews9 followers
April 25, 2022
3.5 stars

You know those authors who hint at things to come, and even when it comes it is interesting/shocking/surprising enough to make the hints worth it without being annoying? Yeah, this isn't one of those unfortunately. There was so much build up - if only she had told her this, or done that, then this might not have happened! I really didn't see how any of the things that Kate might have said or done would have prevented any of the choices her sister, Bec made. The choices Bec made were very much related to her marriage and who she had become within that marriage.


Kate, who was a model before becoming an amputee, could have been an interesting character. I did find some of the things in her life difficult to believe - she was a top model, and now as an amputee no one wants to date her? for what 15 years or whatever it was? It just seemed unlikely, especially in a city the size of Melbourne. I guess that the amputees or limb difference people that I follow tend to be sportspeople, so maybe that makes a difference. But anyway, I didn't find that convincing.

Right, after that, I am changing it to 3 stars rounding up, because I am cross again, haha.

When everything finally comes to a head, it seems tacked on a bit, and kind of a let down in many ways, which was a bit of a let down.
Profile Image for Pam.
46 reviews
June 28, 2021
Great debut novel Katie, very proud to say I know your Mum. Took me a while to get into but then it sweeps you along with one thing after another each time changing your mind about the two families. Great twists & turns kept me guessing until the end
Profile Image for Philippa.
509 reviews
July 2, 2021
I could barely put this down - imagine Big Little Lies but set in Hobart and Melbourne! Fabulous.
1,500 reviews22 followers
November 7, 2022
Bec and Kate are sisters, but their lives are so different from each other. Bec is happily married with children, but is she really happy? When Ryan shows up in her life, Bec considers what it would be like to be young and carefree again. Kate is lonely, choosing to live far away from family. When she meets Adam, she is thrilled. But she's sure he's hiding something when he continually evades answering questions about his life. One of these sisters will make a huge mistake and it will affect both their lives.

It took me a while to get into this novel, it was plodding along nice and slow until something switched after the halfway point and I found myself getting more and more invested. What started off as a slow burn became a fast paced twisted ending. And the way the book all came together at the end - so very clever! Loved this Aussie debut novel. I have already read Katie's newer book The Accident, which is also fabulous. If you haven't read her books yet, do yourself a favour and pick one up.
Profile Image for Gabriela Bourke.
106 reviews
August 19, 2024
Went directly to McMahon’s debut after reading her more recent novel. I never expect first books to be as good - but this was if anything better. Brilliant characterisation, gripping story, just such a sound and satisfying piece of writing. Cannot wait for another from this author.
Profile Image for Allyt_hobart.
240 reviews2 followers
May 7, 2021
Holiday reading
Quickly consumed (and forgotten)
Lots to enjoy with a fast paced engaging style but too much implausibility and coincidence and far too neatly resolved.
Profile Image for Amy Ursula.
189 reviews
November 16, 2022
It wasn't a terrible read, just not a book I'm eager to share with friends.
I was keen for the local vibe, but felt it was weird that so many place names were changed in the story.
The drama of it all was a bit more than I had anticipated. I just didn't love it - was it a mistake to buy it...?
Displaying 1 - 30 of 178 reviews

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