When a Hallowe'en party turns deadly, it falls to Hercule Poirot to unmask a murderer. At a Hallowe'en party, Joyce—a surly thirteen-year-old—boasts that she once witnessed a murder. When no one believes her, she storms off. But within hours her body is found, still in the house, drowned in an apple-bobbing tub.

Famed detective Hercule Poirot is called in to investigate. Set against a night of trickery and the occult, it’s up to Poirot to uncover the real evil presence responsible for this ghastly deed.