The Stepsister’s Secret

She’s family now. But can I trust her?

When my stepsister Alison moves in to look after my mother, everyone in my family is grateful. Alison’s a nurse, and she says she just wants to help. But I don’t trust her.

Years ago, when Alison and I were the same age as my own son Isaac, I made a terrible mistake that tore Alison’s world apart. Now the look in her icy blue eyes tells me: she knows exactly what I did.

I’m certain she’s responsible for my mother getting weaker. I don’t like the way she’s pushing me out, isolating me… and getting way too close to my husband, Nick.

I’m watching her. And I’ll do anything to keep my family safe. But I have no idea just how much danger we’re in…

A totally unputdownable, twisty story of family secrets that have deadly consequences. Perfect for fans of Shari Lapena, Freida McFadden, and Daniel Hurst.

What readers are saying about Karen King:

‘Wow, I could not put this down… I devoured it in one sitting… Had me hooked from the first chapter…. Left me speechless… kept me guessing until the very last page!’ Arcreviews_by_m, ⭐⭐⭐⭐⭐

‘Omg I absolutely loved this book and couldn’t put it down! Full of suspense, shouting out loud noooooo or wtf moments! Highly recommend.’ NetGalley reviewer, ⭐⭐⭐⭐⭐

‘HOLY SMOKES! You will not want to put this book down. Talk about a gripping story. I could not get enough of this.’ NetGalley reviewer, ⭐⭐⭐⭐⭐

‘Cannot give this book enough stars!!!… I was actually annoyed I had to go to uni and stop reading it for a few hours… Absolutely outstanding.’ Itsa.bookstory, ⭐⭐⭐⭐⭐

‘Excellent… Full of brilliant twists and turns… WoW… Superb… guessing till the very end! Excellent!’ Goodreads reviewer, ⭐⭐⭐⭐⭐

‘Wow… Absolutely brilliant. I couldn’t put it down… A real page turner.’ Goodreads reviewer, ⭐⭐⭐⭐⭐

‘One of my favorites of 2025… An amazing fast-paced thriller that you can read in one sitting.’ Nath.readingadventures, ⭐⭐⭐⭐⭐

‘Mind-blowing read. Loved it.’ NetGalley reviewer, ⭐⭐⭐⭐⭐

‘Brilliant… just mind-blowing…. I was hooked… It’s just superb.’ NetGalley reviewer, ⭐⭐⭐⭐

‘An absolute rollercoaster, packed with thrills and suspense.’ Goodreads reviewer, ⭐⭐⭐⭐⭐

‘So many twists and turns that I never saw coming… Couldn’t stop reading it.’ Goodreads reviewer, ⭐⭐⭐⭐⭐