Famous crime novelist Ariadne Oliver is invited to a Halloween Party for the local teenagers. During her preparations for the party, the conversation turns to Ariadne's grisly novels. One of the teenagers boasts that she once witnessed a murder, although she didn't realize at the time what she'd seen. Convinced that she is just trying to attract attention, no one believes her--but later she is found tragically drowned in an apple-bobbing tub. Distraught, Ariadne decides to call upon the services of her old friend Hercule Poirot to solve the case. Assuming that Joyce was killed because of what she said, Poirot knows he must find out if the teenager was telling the truth. If so, there is not just one death for him to investigate, but two.