In this sensational thriller from the number-one internationally bestselling author, two sisters discover that the secrets they keep from each other prove to be deadly.

You've known her all your life. Or have you?

Tasha and her older sister Alice may look alike, but they couldn't be more different. Tasha's married with two children and still lives in their hometown near Bristol. Alice is a high-flying scientist who travels the world with her equally successful husband.

Yet each sister would trust the other with her life.

When Tasha and her husband Aaron need a break and Alice offers to stay in their home with the kids, Tasha knows her family is in safe hands.

She couldn't be more wrong.

The call from home is devastating. Alice and her husband Kyle have been attacked, leaving Alice in intensive care and Kyle dead. Rushing to the hospital, Tasha finds the police trying to piece events together. She can't think why anyone would attack her sister.

Then the note arrives, addressed to Tasha:

It was supposed to be you . . .

Every family has secrets. Some more deadly than others.