Setting and Opening

The story begins with the famous Belgian detective, Hercule Poirot, traveling on the Taurus Express from Aleppo to Istanbul. Upon arrival, he receives a telegram summoning him back to London. In Istanbul, Poirot books a ticket on the legendary Orient Express, which is unusually crowded for the season. Thanks to his friend Monsieur Bouc, director of the train company, Poirot secures a first‑class compartment—even though the train is fully booked.

On board, Poirot notices a varied group of passengers: Americans, Europeans, and aristocrats. Among them are Mr. Ratchett, an unsettling American who later asks Poirot to protect him, and his secretary Hector MacQueen.

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The Murder

The night is interrupted by ominous signs: Poirot hears a cry from Ratchett’s room. The conductor checks on him, but Ratchett dismisses it. Mrs. Hubbard, one of the passengers, reports a man entering her cabin. Outside, the train is stuck in a snowdrift. Poirot eventually falls asleep, but hears a loud thump nearby.

When morning comes, Bouc informs Poirot that Ratchett has been murdered—stabbed in his locked compartment, and the murderer is still aboard since the train is snowed in. Poirot volunteers to investigate, with Bouc and Dr. Constantine assisting.

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Clues and Investigation

Inside the compartment, Poirot finds twelve stab wounds, an open window with no footprints, a monogrammed handkerchief, a pipe cleaner, a foreign match, and a burnt scrap of paper reading “Daisy Armstrong”.

The Daisy Armstrong clue triggers Poirot’s memory of a famous kidnapping in America. A young girl, Daisy, was kidnapped and killed. The ransom paid did not save her. Sonia Armstrong, Daisy’s mother, died of shock, and her husband killed himself. The family’s French nurse was wrongly accused and also died by suicide. Despite being accused, gangster Cassetti escaped justice due to corruption.

Poirot realizes Ratchett isn’t truly Ratchett; he’s actually Cassetti under a false name.

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Passenger Interviews

Poirot interviews each passenger. They all claim innocence, and many provide airtight alibis, verified by others. Still, strange details emerge:

• Mrs. Hubbard says someone was knocking on her door, but her connecting door to Ratchett’s room was locked.
• Several passengers mention seeing a woman in a scarlet kimono in the corridor, yet no one claims that kimono.
• A uniform button found near Hubbard’s cabin ties to the conductor’s coat.
• A pipe cleaner might implicate pipe smoker Colonel Arbuthnot, but he brushes it off
• The burnt note with Daisy’s name confirms Ratchett’s real identity.

Poirot also observes oddities in luggage: Countess Andrenyi’s wet luggage tag and Schmidt’s bag containing a uniform. The kimono is mysteriously found in Poirot’s own baggage.

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Piecing It Together

Poirot, Bouc, and Dr. Constantine review all the clues. Poirot enters a deep, thoughtful trance, emerging with a shocking conclusion: all of the clues may have been planted to mislead.

He compiles a list of each passenger’s connections to the Armstrong tragedy:

1. Mrs. Hubbard is actually Linda Arden, Daisy’s grandmother.
2. Countess Andrenyi is Helena Goldenberg, Daisy’s aunt.
3. Mary Debenham was Daisy’s governess.
4. Foscarelli was the Armstrong chauffeur.
5. Masterman was Colonel Armstrong’s valet.
6. Greta Ohlsson was Daisy’s nursemaid.
7. Princess Dragomiroff was Sonia Armstrong’s godmother.
8. Schmidt was the family cook.
9. Pierre Michel, the conductor, is related to the nursemaid.
10. Hardman (an assumed alias) was a private detective in love with the nursemaid.
11. Colonel Arbuthnot was a close friend of Colonel Armstrong.
12. MacQueen is the son of the lawyer who prosecuted the nursemaid.

All of them had reasons to hate Cassetti and the legal system that failed Daisy’s family.

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Two Solutions

Poirot presents two possible explanations to Bouc, Dr. Constantine, and the passengers:

• Solution One: A mysterious outsider boarded in Yugoslavia wearing a uniform, killed Ratchett, then escaped, leaving false clues.
• Solution Two: The 12 people aboard (passengers plus conductor) conspired and each stabbed Cassetti. The varying wounds and planted items were meant to disguise the collective act.

Mrs. Hubbard (Linda Arden) confesses that the second solution is truth. She planned and orchestrated the groupkill. However, Bouc and Dr. Constantine choose to report the first solution—an unknown killer escaped—arguing that this spares all involved from legal punishment and serves moral justice.

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Themes and Tone

This novel is often described as a locked‑room mystery and a masterpiece of detective fiction . Poirot’s famous line in the story is:

The impossible could not have happened, therefore the impossible must be possible in spite of appearances.

Christie explores themes of justice versus the law. Everyone acted out of grief and moral outrage. The official verdict is left open so that the compassionate resolution—punishment by the victims’ relatives—is accepted over legal justice. Poirot himself is morally conflicted but reaches a practical resolution.

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Final Reflection

The novel ends with Poirot leaving the Orient Express. He is torn by his decision but accepts that sometimes moral justice must override legal justice. He tells the police the stranger killed Ratchett, allowing the 12 conspirators to go free when the train resumes its journey southward.