It is a windy and cold morning in Syria. At five o’clock in the morning, Detective Hercule Poirot is entering the Taurus Express. He’s on his way to Stamboul (Istanbul) for a vacation of a few days in length. As Poirot boards the Tarus Express, Lieutenant Dubosc is profuse in his thanks for Poirot’s assistance. Lieutenant Dubosc says, "You have saved us mon cher...you have saved the honor of the French Army." Poirot replies to this by saying, "But indeed, do I not remember that you once saved my life?" Poirot spends some more time exchanging pleasantries with the General. He then boards the train. Once on the train, he soon comes across Colonel Arbuthnot and Mary Debenham. Poirot first sees Colonel Arbuthnot at breakfast that very morning. As he sips coffee, Poirot watches everything Arbuthnot and Debenham do. Arbuthnot comes up to Debenham, who is already enjoying breakfast, and he inquires if he might join her. The two people are “not chatty,” and this is said to be “true to their English nationality.” A fire under the train’s dining car causes the train to stop at two-thirty. This makes Mary Debenham very anxious, and she confides in Poirot that she cannot miss her connection to the Simpleton Orient Express. Poirot watches Mary and the Colonel become more friendly as the voyage to Istanbul progresses, and he overhears them have conversations that make him curious. As she looks out over the scenery through the window, Mary says to Arbuthnot that she yearns to enjoy the countryside. Poirot and the couple exit the train to stretch their legs at the Konya stop. During this time, Poirot overhears Mary and Arbuthnot speaking. Mary says to Debenham, "When it's all over. When it's behind us—then—."
When Poirot arrives in Stamboul, he checks into the Tokatlian Hotel. He finds there is a telegram and three letters waiting for him there. The telegrams communicates that there has been a development in the Kasner case and that, as a result, he is obliged to return to London. Poirot books a room on the Simpleton Orient Express. This train will depart at nine that night. Poirot meets up with M. Bouc, an old friend, in the hotel restaurant. M. Bouc is director of the Compagnie Internationale des Wagons Lits. He will accompany Poirot on the train. As Poirot eats a meal in the restaurant, his interest is attracted by two men. These are Ratchett and Hector McQueen, who are sitting at a nearby table. Poirot immediately believes that Ratchett is untrustworthy. Once Poirot has finished his meal, he goes to the lounge to meet M. Bouc. When the concierge enters, he informs Poirot that there are no first-class apartments currently available. The concierge seems surprised at this fact, and he remarks that "All the world elects to travel to-night!" M. Bouc makes arrangements for Poirot to use the carriage of Mr. Harris, as this man has not yet boarded the train. Poirot and Hector McQueen share the carriage. Hector McQueen is the same young man that was with Ratchett in the restaurant.
Bouc and Poirot lunch together the next day. As they eat, Poirot looks about himself at the other thirteen passengers. There are a “big, swarthy Italian;” a large American, a tidy Englishman, and a lady that Poirot thinks one of the “ugliest old ladies he had ever seen.” This lady is Princess Dragomiroff. Poirot also sees Mary Debenham sitting along with two other women. Colonel Arbuthnot is by himself. There is also a Scandinavian woman who appears to be middle aged, a couple who seems to be English, Ratchett, and Hector McQueen. Once the dining car begins to empty, Ratchett approaches and sits opposite to Poirot. Ratchett says to Poirot that his life is in jeopardy and that he has enemies. He declares that he will give Poirot “big money” if he will protect him. Poirot informs Ratchett of the fact that he only takes cases that specifically “interest him.” Ratchet inquires as to why Poirot will not take his case. Poirot declares: “I do not like your face.”