'I just couldn't put this book down, and ended up reading until 1.30am... What a roller coaster of a ride! Absolutely loved it!' Goodreads reviewer ? ? ? ? ?

She knows you better than you know yourself.

Karen is meant to be the one who fixes problems.

It's her job, as a psychiatrist - and it's always been her role as a friend.

But Jessica is different. She should be the patient, the one that Karen helps.

But she knows things about Karen. Her friends, her personal life. Things no patient should know.

And Karen is starting to wonder if she should have let her in . . .

A chilling, unputdownable thriller from the bestselling author of How I Lost You. Fans of Claire Douglas, Gillian McAllister and Cara Hunter.