When Johnny Matlock whisks away a cold war secret from under the noses of Berlin's top secret agents, his every move is followed when he returns to England. 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.