Based on the novel by Edgar Wallace, detectives at Scotland Yard try and track down The Crimson Circle, a secret society of blackmailers

While holding a séance for skeptical novelist Charles Condomine, self-proclaimed 'spiritualist medium' Madame Arcati inadvertently summons the spirit of his deceased first wife Elvira, leading to an increasingly complex love triangle with Ruth, his current wife of five years.

While vacationing in St. Moritz, a British couple receive a clue to an imminent assassination attempt, only to learn that their daughter has been kidnapped to keep them quiet.