Mrs. Bradley and chauffeur George visit a seaside village to wish Inspector Christmas a happy retirement and find themselves investigating the murder of Chastity Baines, the daughter of Reverend Baines. Wrapped around the dead girl's neck is a worsted viper with her ring stuffed in its mouth. The circumstances remind Mrs. Bradley of her first case involving a cult led by Black Jack Briggs that killed virgins. George's daughter lives in the villages and he is shocked to learn that his daughter is engaged to be married. Things become serious when she is kidnapped and may be the cult's next victim.