Elizabeth II's coronation is looming, but the murder of their wartime commander, Colonel Cartwright, spoils the happy mood for DI Edgar Stephens and magician Max Mephisto. A playbill featuring another deceased comrade is found in Colonel Cartwright's possession, and a playing card, the ace of hearts: the blood card. Stephens and Mephisto are summoned to the case. Recalls the best of Agatha Christie.