When Claire Cooper was eight, her mother disappeared during Hop-tu-naa, the Manx Halloween. When Claire was 18, she and her friends took part in a Hop-tu-naa dare that went terribly wrong. Now that she is in her early 20s and a police officer, what happened that Hop-tu-naa night has come back to haunt them all, and Claire must confront her deepest fears in order to stop a killer from striking again.