Summary: Chapter 1

It is five o'clock on a cold windy morning in Syria. Detective Hercule Poirot is boarding the Taurus Express on his way to Stamboul (Istanbul) for a few days of vacation. As he boards the train Lieutenant Dubosc profusely thanks Poirot for his help, "You have saved us mon have saved the honor of the French Army." To which Poirot replies, "But indeed, do I not remember that you once saved my life?" After exchanging more pleasantries with the General, Poirot boards the train. On the train he is accompanied by Mary Debenham and Colonel Arbuthnot whom Hercule first encounters at breakfast that same morning. While sipping coffee, Poirot observes every detail of Arbuthnot and Debenham. Arbuthnot approaches Debenham, already eating breakfast, and asks if he might join her. The two, "true to their English nationality," were "not chatty." At two-thirty the train comes to a halt because of a fire under the dining car. Mary Debenham is extremely anxious and tells Poirot that she must not miss her connection to the Simpleton Orient Express. Poirot observes the Mary and the Colonel become increasingly friendly over the course of their voyage to Istanbul and overhears conversations between them that peak his detective's curiosity. While looking out at the scenery, Mary remarks to Arbuthnot that she wishes she could enjoy the countryside. And, at the Konya stop, when Poirot and the couple get out to stretch their legs, Poirot hears Arbuthnot and Mary speaking together; Mary says to Debenham, "When it's all over. When it's behind us—then—."

Summary: Chapter 2

Poirot arrives in Stamboul and checks in at the Tokatlian Hotel. There are three letters and a telegram waiting for him. The telegram informs him that there is a development in the Kasner case and he must return to London. Poirot arranges a room on the Simpleton Orient Express, which will leave at nine that evening. In the hotel restaurant Poirot meets up with an old friend M. Bouc, director of the Compagnie Internationale des Wagons Lits, who will accompany him on the train. While eating in the restaurant, Poirot takes interest in two men, Ratchett and Hector McQueen, at a nearby table. Poirot is immediately distrustful of Ratchett. After Poirot finishes his meal he meets M. Bouc in the lounge. The concierge enters and tells Poirot there are no first class apartments available. Surprised at the full train, he remarks to Poirot, "All the world elects to travel to-night!" M. Bouc arranges for Poirot to take the carriage of Mr. Harris, a man who has not yet shown up for the train. Poirot shares the carriage with Hector McQueen-the same young man he saw with Ratchett in the restaurant.

Summary: Chapter 3

The next day M. Bouc lunches with Poirot. While the two men sit and eat, Poirot looks around at the other thirteen passengers: a "big, swarthy Italian;" a neat Englishman; a big American; one of the "ugliest old ladies he had ever seen," Princess Dragomiroff; Mary Debenham sitting with two other women; Colonel Arbuthnot by himself; a middle-aged Scandinavian woman; an English-looking couple and, lastly, Hector McQueen and Ratchett. The dining car empties and Ratchett comes and sits opposite Poirot. Ratchett tells Poirot that he has enemies and that his life is threatened. He offers Poirot "big money" to protect him. Poirot tells Ratchett that he only takes cases that "interest him." Ratchett asks Poirot why he won't take the case. Poirot replies, "I do not like your face."

Analysis: Chapters 1–3

The character of Hercule Poirot is set up and detailed in the first three chapters. The personality traits and ticks he displays in these chapters not only color him and make him an incredibly interesting character, but help set up his motivations and detective techniques for the rest of the novel.

Poirot is introduced as the "Belgian stranger" that has some connection with a suicide, a General and the French Army, all very suspicious and left purposefully ambiguous. From the point of view of Lieutenant Dubosc, Poirot is described as a mysterious, small man "muffled up to the ears of whom nothing was visible but a pink tipped nose and an upward curled moustache." It is only in the first few chapters that Poirot is scrutinized from another character's perspective; from then on the reader mainly concentrates on the murder suspects. Poirot's moustache is another particularly wonderful detail, especially in Chapter 2 as he makes pains to keep it out of his soup.

He is described as being short, worrisome and self-conscious. Poirot probably does not have a family, as they are never mentioned and are not on vacation with him, but is a single bachelor that has little interest in women. Poirot is not an infallible character, but has insecurities and issues like the rest of the passengers.

The reader immediately knows that Poirot is obviously a trained and successful detective. It is one of the keys to his success is his attention to detail. He observes and analyses every person he encounters—not just physical traits, but how a person acts and interacts with others. A good example of this is the relationship between Colonel Arbuthnot and Mary Debenham on the train. Poirot becomes suspicious because of their quick familiarity to each other. Are they really strangers? Poirot immediately observes Mary's cool and calculated demeanor, strict English manners and efficiency too great to be called "joie femme." Later in the novel, these observations make Poirot think this woman might be capable of murder and are essential to his solving the case.

Poirot is a nosy man, a trait that makes him a great detective. The conversations Poirot eavesdrops on, between Arbuthnot and Debenham, help him solve the Orient Express murder later on. Mary's comment, "Not now. Not now. When it's all over. When it's behind us—then—," her anxious behavior when the train stops and her remark to Arbuthnot that she wishes she could enjoy the landscape all make Poirot suspicious that she is hiding something or about to be engaged in something bad. Poirot's suspicions and Christie's attention to these particular conversations purposely foreshadow the ending of the book.

When Poirot arrives at the hotel, his observations of Ratchett and McQueen in the dining room prove equally important in terms of foreshadowing. Ratchett immediately "captured the detective's attention" and convince Poirot that he is dangerous, a "wild animal." Poirot's negative feelings and initial reaction toward Ratchett are extremely important because they make the reader and Poirot sympathize with the Armstrong family later in the book. Describing Ratchett as a "wild animal," something less than human, renders the murder less offensive. The murderer, then, has slain a beast rather than a human being.