When Jonny Matlock whisks away a cold war secret from under the noses of Berlin's top secret agents, his every move is followed upon his return to England. On a deserted country road he is set upon and knocked unconscious by enemy agents. His girlfriend Paula is kidnapped but her handbag is discovered at the scene of the crime by the aristocratic private eye, Duke Martin. Inside it he discovers the secret formula that the agents are searching for and tracks down her sister Paula. As Johnny grows frantic for the safe return of his girlfriend, Duke Martin plays a deadly game of double bluff with the enemy agents. This fast paced British movie features a catalogue of talented actors and stalwarts such as Michael Balfour and Freddie Mills, plus an overlooked cameo appearance from Arthur Lowe.