Hercule Poirot is called in by his novelist friend Ariadne Oliver who attended a Hallowe'en party at the home of Rowena Drake in Woodleigh Common, at which 13-year-old Joyce Reynolds has been drowned in an apple-bobbing tub. Joyce had earlier told everyone that she had witnessed a murder but didn't recognise it as a murder until a year later. Investigating the murder, Poirot compiles a list of recent deaths and missing persons in the area. Rowena's aunt had died, and shortly afterward, a codicil in her will favoring her au pair girl Olga Seminoff was found to be a forgery, after which Olga had disappeared. Other recent murder victims included a shop assistant, a schoolteacher and a lawyer's clerk. Ariadne's friend Judith has a daughter Miranda, who was Joyce's closest friend, and may be able to shed light on the mystery.
This work contains examples of the following tropes:
- Asshole Victim: Joyce manages to be a prepubescent version of this trope, being regarded by most of the adults and children around her as a lying attention-seeker and not incredibly well-liked as a result. Her younger brother Leopold, a blackmailer, also counts.
- Attention Whore: Joyce is known to tell fabricated stories for attention.
- Big Damn Heroes: Nicholas and Desmond rush in to save Miranda from being poisoned by Michael Garfield.
- Blackmail Backfire: Joyce's brother Leopold blackmails Rowena Drake, whom he observed murdering his sister. He is killed for it, true to Agatha Christie form.
- Does This Remind You of Anything?: Ariadne mentions that she likes apples. One of the teenage boys replies that "It would be more fun if they were melons. They're so juicy. Think of the mess it would make."
- Halloween Episode: The first murder of the story takes place at a Hallowe'en Party in Woodleigh Common.
- Human Sacrifice: Garfield attempts this on Miranda, having been grooming her for it, and ultimately goading her to an altar where he attempts to poison her, telling her to "drink to beauty".
- The Ingenue: Miranda Butler, in stark contrast to both her father, Michael Garfield, and her best friend, Joyce. When she witnessed a murder from above, her first thought was that perhaps she oughtn't to have been there; when she tells the story to Joyce, she had no idea that Joyce would make it her own and get herself murdered for it. Feeling responsible for Joyce's death, Miranda is extra susceptible to Michael's conditioning of her to accept the role of a sacrifice victim. Poirot lampshades this trope after Miranda is rescued.
- Mad Artist: Michael Garfield, in spades. His murders are motivated by nothing other than his narcissistic desire to construct a beautiful garden on a Greek island, and to have the money to afford this.
- Not Afraid to Die: Miranda has been groomed by Michael Garfield to see herself as an appropriate sacrifice victim, compunded by her feeling of responsibility for Joyce's death. Luckily, she is rescued.
- Offing the Offspring: Michael Garfield tries to kill his own biological daughter, Miranda Butler, because she had witnessed him disposing of a murder victim and would thus be a threat to his plans. He even gives her the nickname "Iphigenia", referring to the daughter Agamemnon sacrificed.