When Nora takes the train from London to visit her sister in the countryside she expects to find her waiting at the station, or at home cooking dinner. But when she walks into Rachel's familiar house, she finds her brutally murdered. Stunned and adrift, Nora can't return to her former life. An unsolved assault in the past has shaken her faith in the police, and she can't trust them to find her sister's killer. As Nora takes the investigation into her own hands, she unearths terrifying secrets that make her sister almost unrecognisable.