The story opens with Poirot embarking on a flight between Paris and London. He and the other passengers settle themselves for the journey, marred only by the presence of a stowaway wasp which is quickly killed by one of the passengers. The situation changes when a steward tries to wake one of the passengers in preparation for landing. She has died during the flight.
Poirot sets out to solve the crime which appears to have been committed by using a dart tipped with snake venom shot from a blowgun. All the passengers are under suspicion and have lives that are surprising intertwined. The trail leads Poirot from London, to the English countryside and back to Paris with inquiries stretching halfway around the world. In the end Poirot is, of course, triumphant. He even manages to help true love along the way.
Even though this is very much a period piece the mystery is intriging and Christie comes through with one of her characteristic surprise twists.