Ulysses Diello (Mason) is a diligent valet to the British ambassador (Hampden) in neutral Turkey during World War II. Tired of his subservient, dead-end position, he photographs many top secret diplomatic documents and sells them at a high price to the Germans, even though they suspect the information to be false. With the help of an aristocratic but penniless Countess (Darrieux), he amasses a fortune. But can the spy codenamed Cicero escape to South America before a British intelligence officer (Rennie) discloses his identity?

Based on the story of real-life spy Elyesa Bazna, this engrossing thriller unfolds in almost documentary-like detail, until the cinematic excitement heats up for the third act denouement. Mason is commanding as a man swallowing a lifetime of resentment; his performance is coiled, his face a mask of cunning and concealment. The Oscar-nominated screenplay (by Michael Wilson and an uncredited Mankiewicz) crackles, especially in the loaded exchanges between Mason and Darrieux, seductively charming as the ambitious refugee. Exteriors shot on location in Ankara add authenticity to the proceedings. “Fingers” marks yet another cinematic triumph for a director at the peak of his form.