Hallowe'en Party

S12, E2: Agatha Christie's Belgian sleuth is called in by an old friend to investigate a drowning, only to uncover a series of mysterious deaths. Novelist Ariadne Oliver attends a Hallowe'en party in Woodleigh Common. During the spooky festivities, she hears young Joyce Reynolds boast of having witnessed a murder years before. The story is heard by everyone present, including her brother, hostess Rowena Drake and the local vicar. Later that evening, Joyce is found drowned in an apple-bobbing bucket, and Ariadne calls in her old friend Hercule Poirot to investigate. Although the local police do not take Joyce's claim seriously, Poirot soon uncovers a series of strange deaths in the village, and realises that Joyce could have seen any of them. Then another child is found drowned. Can Poirot solve the mystery and prevent any further tragedies?