Fran is very upset because her mother has remarried and she has to live with her stepfather and his son at her gran's old home. She was very fond of her gran, who has recently been found dead in the nearby river. Was her death an accident? Fran is sure someone is to blame and she's determined to solve the mystery. Is the weird girl, Fay, who lives next door, hiding something? And why does another new friend, Denny, warn her against Fay's strange magic? Fran faces danger when the river almost claims a new victim, before she finally unlocks its secrets in a surprising and exciting climax to the story.