Hallowe'en Party (Book 41)

Trick or treat? No one believes Joyce Reynolds when she boasts she once witnessed a murder. Until, that is, she is found drowned, face down in an apple-bobbing tub. What exactly was it she saw? Then the victim's brother is found drowned too, and the mysteries multiply. Hercule Poirot and Ariadne Oliver must race to get at the truth, and prevent further tragedy.