# Hercule Poirot — The Mystery of the Blue Train character guide > Hercule Poirot in The Mystery of the Blue Train by Agatha Christie. **Role:** major **Also known as:** M. Poirot, Monsieur Hercule Poirot, Monsieur Poirot, the Hercule Poirot **First appearance:** 0002-i-the-man-with-the-white-hair ## Snapshot A quiet Belgian detective who boards the Blue Train to reconstruct a murder, turning every passenger into a suspect with a smile. ## Who they are Poirot arrives in this case not as a policeman but as a consultant summoned by a grieving millionaire, and he insists on riding the very train where the crime occurred. His methods are theatrical and precise: he acts out the maid's panic, the wife's surprise, the husband's discovery, testing each possibility against the cramped geography of a sleeping car. The tension lies in his unhurried certainty, which unnerves clients who want immediate answers. He matters because his refusal to accept the obvious suspect reshapes the entire investigation. ## Relationships ### [Katherine Grey](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/characters/katherine_grey) _friendship_ Poirot respects Katherine's intelligence and integrity, forming a trusting alliance during the investigation. ### [Ruth Kettering](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/characters/ruth_kettering) _professional_ Poirot investigates Ruth's murder, interacting with her primarily through clues and witness accounts. ### [Derek Kettering](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/characters/derek_kettering) _rivalry_ Derek is initially hostile and suspicious of Poirot's investigation, fearing he will be accused. ### [Major Knighton](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/characters/major_knighton) _professional_ Poirot interviews Knighton as a key witness and assistant in the case, maintaining polite cooperation. ### [Comte de la Roche](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/characters/comte_de_la_roche) _rivalry_ The Comte is a prime suspect and tries to outmaneuver Poirot, leading to tense confrontations. ### [M. Papopolous](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/characters/m_papopolous) _professional_ Poirot consults Papopolous, an antique dealer, for information about stolen jewels. ### [Lenox Tamplin](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/characters/lenox_tamplin) _friendship_ Poirot finds Lenox a sensible and helpful ally during his stay at the villa. ### [Zia](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/characters/zia) _professional_ Zia, a maid, provides Poirot with key observations about the household. ### [George](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/characters/george) _professional_ George is Poirot's loyal valet, assisting him with travel and daily needs. ### [Katherine Grey](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/characters/katherine_grey) _friendship_ Poirot respects Katherine's intelligence and integrity, forming a trusting alliance during the investigation. ### [Ruth Kettering](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/characters/ruth_kettering) _professional_ Poirot investigates Ruth's murder, interacting with her primarily through clues and witness accounts. ### [Derek Kettering](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/characters/derek_kettering) _rivalry_ Derek is initially hostile and suspicious of Poirot's investigation, fearing he will be accused. ## In the story ### [The Mystery of the Blue Train](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/the-mystery-of-the-blue-train) The famed detective who is called upon to investigate the murder aboard the Blue Train. ### [X: On the Blue Train](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/x-on-the-blue-train) Dines opposite Katherine Grey; discusses detective novels and hints at future adventures. ### [XI: Murder](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xi-murder) Present during the police questioning; examines the compartment and notes the strange post-mortem blow; invites Katherine to join the investigation. ### [XIV: Ada Mason's Story](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xiv-ada-mason-s-story) Present at the interrogation, offers his services to Van Aldin, and acts as interpreter. ### [The Comte de la Roche](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xv-the-comte-de-la-roche) Questions the Comte's psychology as a murderer and reveals his knowledge of the Comte's whereabouts. ### [XVI: Poirot Discusses the Case](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xvi-poirot-discusses-the-case) Poirot leads the discussion, challenges the police's theory, and agrees to work for Van Aldin. ### [An Aristocratic Gentleman](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xvii-an-aristocratic-gentleman) Observes Kettering's reactions and notes the discrepancy about the rubies; later questions the maid about the tickets. ### [Katherine Makes a Friend](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xx-katherine-makes-a-friend) Calls Katherine to arrange a meeting with Van Aldin, picks her up in an auto, discusses the case and the Comte de la Roche's alibi. ### [At the Tennis](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xxi-at-the-tennis) Arranges to meet everyone at the tennis; produces a cigarette case and later reveals the recovered rubies to Van Aldin. ### [M. Papopolous Breakfasts](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xxii-m-papopolous-breakfasts) Visits M. Papopolous early in the morning, shows him the imitation rubies, and seeks his help in the murder investigation. Later sends a coded telegram to Inspector Japp. ### [A New Theory](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xxiii-a-new-theory) Presents his new theory to Van Aldin, re-interviews Ada Mason, and reveals the jewels were imitations. ### [XXIV: Poirot Gives Advice](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xxiv-poirot-gives-advice) Explains his theory of the crime to Van Aldin, warns Derek about Mirelle, and receives confirmation from Van Aldin about Mason's identification. ### [A Warning](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xxvi-a-warning) Poirot warns Katherine about a man more dangerous than the Comte de la Roche, implying that the man may be a murderer. ### [Interview with Mirelle](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xxvii-interview-with-mirelle) Accompanies Knighton to interview Mirelle, takes the lead in the conversation, and later questions Mirelle's statement during the official interrogation. ### [XXVIII: Poirot Plays the Squirrel](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xxviii-poirot-plays-the-squirrel) Plays the squirrel, orchestrating meetings and gathering information; visits Lady Tamplin's villa, dines with Papopolous, and confronts Zia. ### [A Letter from Home](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xxix-a-letter-from-home) Visits the Villa Marina to confront Hipolyte and Marie about the Comte's arrival; interrogates Mirelle about entering Ruth's compartment. ### [Miss Viner Gives Judgment](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xxx-miss-viner-gives-judgment) Poirot writes to Katherine from Paris, updating her on his inquiries and expressing a desire to meet her in London. ### [XXXI: Mr. Aarons Lunches](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xxxi-mr-aarons-lunches) Hosts Mr. Aarons at lunch and questions him about Kitty Kidd and Mirelle, showing keen interest in the ruby 'Heart of Fire.' ### [XXXII: Katherine and Poirot Compare Notes](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xxxii-katherine-and-poirot-compare-notes) Dines with Katherine at the Savoy, admits dissatisfaction with the case against Derek Kettering, and reveals his investigations in Paris and London. ### [A New Theory](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xxxiii-a-new-theory) Presents a new theory exonerating Derek Kettering and proposes traveling to the south of France. ### [The Blue Train Again](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xxxiv-the-blue-train-again) Orchestrates the reconstruction of the crime on the Blue Train, ultimately exposing Knighton as the murderer. ### [Explanations](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xxxv-explanations) Provides the full explanation of the murder to Van Aldin, detailing his deductive process. ### [By the Sea](https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/chapters/xxxvi-by-the-sea) Sits with Lenox on the terrace, recounts the story he told Van Aldin, and offers her comfort and wisdom. ## Links - HTML: https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/characters/hercule_poirot - Book: https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se - All characters: https://www.betterreads.dev/discover/the_mystery_of_the_blue_train_se/characters