Fifteen-year-old Bethany Trent vanishes without a trace from a sunny Cambridge park and for the next four years her sister Claire holds onto the hope of finding her alive. But when Claire inherits her mum's house she discovers a body in the garden which the police had already searched. After a family tragedy DI Ronnie Blake relocates to Cambridge to live with her brother Alex and nephew Noah. Although preferring to work alone she is put in charge of the small but disorderly missing persons' team who first investigated Bethany's disappearance. As Ronnie begins to uncover the clues in the original case notes and the secrets kept by Bethany's family she realises that the killer is playing a complex and deadly game. Ronnie needs to use her wits and unite her dysfunctional team to discover why Bethany had to die.