Renowned stage actor Sir Charles Cartwright hosts a dinner party at his home in Cornwall. His guests include: Hercule Poirot; psychiatrist Sir Bartholomew Strange; Hermione “Egg” Lytton Gore and her mother; Captain Dacres and his wife Cynthia; the playwright Muriel Wills; Egg’s friend Oliver Manders; Mr Satterthwaite; and Reverend Babbington and his wife. When the Reverend Babbington suddenly dies after sipping one of the cocktails being served, Cartwright believes it was murder, though Strange finds no poison in his glass.