gave Paynter an injection of yellow jasmine. A month later, Japp informs Poirot of another mysterious death—that of chess grandmaster Gilmour Wilson, who died from heart failure while participating in a match with Russian refugee Doctor Savaronoff. Poirot deduces that the real Savaronoff died in Russia and that Number Four impersonated him, killing Wilson in order to preserve his cover. Hastings is kidnapped by the Big Four and Poirot saves him. Poirot identifies Number 4 as an obscure character actor called Claude Darrell. A former girlfriend reveals Darrell's identifying quirks. In order to track the Big Four in secret, Poirot stages his own death. He and Hastings travel to the Big Four's mountain hideout in Italy and are taken captive. Poirot reveals that he is not Hercule Poirot, but his twin brother, Achille. He tells the Big Four that the mountain has been cordoned off and the police are on the scene. Three of the Big Four are killed in an explosion just as the police raid the hideout. The other is reported to have committed suicide. Back home, Poirot reveals Achille Poirot did not exist – it was Hercule Poirot in disguise all along. He laments that all his other cases will seem boring and tame compared to this case. The novel ends with Hastings returning to Argentina and Poirot considering retirement. Characters Main Hercule Poirot. The famous private investigator. Having tired of his life in England and dealing with trivial matters, he is tempted to move to Brazil. He has received a monetary offer too good to refuse. Arthur Hastings. Poirot's sidekick in two earlier novels and two short stories. He briefly works as a secretary of Abe Ryland under the alias Arthur Nevill. Inspector Japp. He is an inspector of Scotland Yard. The Big Four A multiethnic gang of four persons working towards world domination. They have a secret hideaway in a quarry of the Dolomites. It is owned by an Italian company which is a front company for Abe Ryland. The quarry conceals a vast subterranean base, hollowed out in the heart of the mountain. From there they use wireless communications to transfer orders to thousands of their followers across many countries. The characters comprise typical ethnic and national stereotypes of 1920s British fiction. They are: Abe Ryland, the so-called American Soap King. He is stated to be richer than John D. Rockefeller and being the