James Mason is "Larry" - a British agent sent on a top secret mission to Turkey. He is soon amidst a conspiracy to dethrone the Sultan and he hasn't a clue whom he can trust. Valerie Hobson - "Tania", an aristocratic refugee from the Russian revolution; Frank Vosper - the superbly seedy "Kazdim" and/or Kay Walsh ("Diana") - take your pick. There are a few (fairly obvious) twists in the story, and ver mais...