When he is eventually arrested and convicted, Colley is approached in prison by Major Adbury, who offers him a deal in exchange for helping with the war effort.

Colley will be given his freedom if he uses his safecracking expertise to perform a mission behind enemy lines.

The dangerous mission is to breach a difficult safe in a Nazi chateau and steal a list of German spies operating in England.

[7] As a curiosity: German soldiers wear helmets with Afrikakorps insignia, probably remnants from a film about Rommel.

In The New York Times, Bosley Crowther called the film "a good, not great, suspense thriller," adding, "The film is full of those tense situations in which the hero slips into a room and opens a safe in terrifying silence.