Sleeping Car to Trieste (1948)

Zurta, a continental adventurer, and Valya, his beautiful companion, board the Orient Express as it leaves Paris. They are tracking Poole, their accomplice in the theft of a diary containing political secrets. Poole has double-crossed them and stolen it. Others soon become involved in the web of intrigue that weaves its way along the corridors of the train: George Grant, a married man travelling with his mistress, who finds his anonymity threatened; a pompous author, MacBain, and his browbeaten secretary; not to mention Monsieur Jolif of the Paris police.