When Claire Cooper was eight years old her mother mysteriously vanished during Hop-tu-naa, the Manx Halloween. At fourteen, Claire is still struggling to come to terms with her disappearance when she's befriended by a group of five teenagers who mark every Hop-tu-naa by performing dares. But Claire's arrival begins to alter the group's dynamic until one year a prank goes terribly wrong, changing all their futures and tearing the friends apart.
Six years later, one of the friends is killed on Hop-tu-naa in an apparent accident. But Claire, now a police officer, has her doubts. Is a single footprint found near the body a deliberate taunt?
As another Hop-tu-naa dawns, bringing with it another death and another footprint, Claire becomes convinced that somebody is seeking vengeance. But who? And which of the friends might be next? If she's to stop a killer and unlock the dark secrets of her past, Claire must confront her deepest fears, before it's too late.