The body of an unknown woman is found in an Edinburgh close and the police are quick to label it as a random act of violence, until that is Detective Constable Faro finds a playing card, the nine of diamonds, planted on the corpse. His superiors scoff at his suspicions, but days later a man is attacked in the street, and left badly bruised and battered with the nine of diamonds in his pocket. Faro seizes on the connection and it is not the last calling card. But what is it that links the victims? Beset by hostile superiors and a policehating public, Faro feels he may never crack this confounding case.