Murder on the Orient Express

Poirot boards the Orient Express after Bouc arranges accommodations for him aboard the luxury train. The passenger list includes many who will later be implicated, from widows to diplomats. Ratchett, who has been receiving threatening letters, tries to hire Poirot for protection, but Poirot declines, sensing something off about him.

An avalanche derails the train's engine, leaving the carriages stranded in a remote pass. The passengers are cut off from the outside world and await rescue. The calm of the journey dissolves into a tense, claustrophobic wait.

In the morning, Ratchett is found murdered, stabbed a dozen times in his compartment. The violent crime shocks the travellers and immediately calls Poirot to action. Bouc and Poirot begin a meticulous investigation to catch the killer among them.

Poirot and Bouc discover burned remnants of one of Ratchett's threatening notes, revealing that Ratchett was actually John Cassetti. Cassetti was responsible for the kidnapping and murder of Daisy Armstrong, linking the murder to a long-ago tragedy. The investigation gains a deeper, personal motive for many passengers.

A bloodstained handkerchief monogrammed with 'H' and a conductor's uniform button are found in Mrs. Hubbard's cabin, suggesting a disguise was planted. The clues hint at a coordinated plan rather than a single killer's motive. Poirot begins to connect these signs to the Armstrong case.

Mrs. Hubbard is stabbed from behind and cannot identify the culprit. The attack adds to the sense that everyone on the carriage might be implicated. Poirot continues his interrogations to uncover connections to the Armstrong family.

During an interview with Debenham, Arbuthnot shoots Poirot in the shoulder and confesses to Ratchett's murder. Bouc incapacitates him before he can kill Poirot. The moment reveals a desperate attempt to control the narrative.

Poirot deduces that Arbuthnot, a former army sniper, deliberately missed the killing shot to misdirect the investigation. The confession is part of a larger, hidden plan to shield others. The investigators push further to uncover the full conspiracy.

Poirot gathers the passengers outside the train and reveals their true identities and shared motive. He concludes they murdered Ratchett together, each delivering a single stab, to avenge Daisy Armstrong. The circle of truth tightens around the group.

Hubbard takes the blame for planning the murder and recruiting the others; Debenham wore the kimono and Arbuthnot staged the stabbing to mislead Poirot. Poirot notes that justice is impossible in this case, as Cassetti deserved death. The passengers accept the moral complexity of their actions.

Poirot offers two verdicts: a lone killer or a collective act of justice. He asks the group to shoot him dead to reveal their willingness to break the law. Hubbard seizes a pistol, but the gun is unloaded, testing their character rather than their resolve.

With the locomotive back on track, Poirot decides to present the lone killer theory to the Yugoslavian police so the others can continue their lives. As he disembarks, a British Army messenger delivers a note asking him to investigate a death on the Nile. A new chapter looms on the horizon.