Famous detective Hercule Poirot is on the Orient Express, but the train is caught in the snow. When one of the passengers is discovered murdered, Poirot immediately starts investigating.

Hercule Poirot is called in to investigate a case for an insurance company regarding firstly a dead woman's body found on a moor and then a important diamond sent to the company to be insured turns out to be a fake. Poirot discovers that the diamond was bought for Arlena Marshall by Sir Horace Platt and Arlena is on her honeymoon with her husband and step-daughter on a tropical island hotel. He joins them on the island and finds that everybody else starts to hate Arlena for different reasons - refusing to do a stage show, stopping a book, and for having an open affair with Patrick Redfern, another guest, in full view of his shy wife. So it's only a matter of time before Arlena turns up dead, strangled and Poirot must find out who it is...