The phone starts vibrating in my hand. It’s my father. He never calls. Pulse racing, I sit up in bed and answer. ‘Caitlin,’ he says. ‘You need to come to the house. Right now. It’s Olivia. She’s back.’

On the night when Caitlin and Olivia’s parents leave them to go to a dinner party, both girls are full of excitement about finally being old enough to stay home alone.

What they don’t see is the figure watching them through the open window. Who, after the girls have fallen asleep, will turn the handle of the unlocked back door.

When their parents return, they will find Olivia’s bed empty. Their eldest daughter gone. Never to return. Until now.

But is the woman who claims to be Olivia all she seems? Is everything Caitlin said she saw that night the whole truth?

Their family have dreamed of this moment, but both sisters are keeping more than one secret. What price will they all pay if they end up believing the wrong daughter?