During the Glasgow Garden Festival the severed head of loan shark Willie Lomax is found in a blocked drain. He is but the first victim in what appears to be a serial killer taking out murderous revenge on loan sharks. Lomax's brother, his unhappy son and the boy's stepfather, however, may provide clues to take the investigation in a different direction.
The body of Rowena Bain is discovered in a wood. The forensic evidence suggests suicide, but Taggart is suspicious. The victim's sister thinks that Rowena's husband, Maurice, killed her. The case against Maurice grows when it is discovered that his first wife also disappeared in mysterious circumstances.