Two thinly connected stories with a weak link in the middle. Milland is an expert safecracker for a London safe-making company who unknowingly falls in with a disreputable antique dealer. This association lands him in jail. The story picks up a couple of years later during the war, when
England needs the services of an expert safecracker. Milland is freed from jail and the drama follows him into German territory on his mission.