Jessica goes on a cruise with her friend Pamela, who has just been released from a sanatorium where she was recovering from the suicide of her husband Johnny. However, on board the ship Pamela is the victim of a terror campaign, and then another passenger is found dead.

Jessica is working a new novel that is based on actual murder case that happened years before. When the private investigator she hired to look into the case is murdered in his office, she and the investigator's partner, tough guy Harry McGraw, reluctantly team up to see which of his cases lead to his death.