Madame Spy (1918)

Robert "Bob" Wesley horrifies his father, Admiral John Wesley of the Naval Advisory Board, by failing his examination at the Annapolis naval academy. Bob seizes the chance to redeem himself, however, when he overhears Hanson, the butler, plotting with German agent Count Von Ornstorff to deliver his father's plans for the Atlantic coastal defenses to German Baroness Von Hulda. In Baltimore, Bob meets the baroness' ship and, with the aid of an old college professor, makes her his prisoner. Having impersonated a woman in the college play, Bob disguises himself as the baroness, rendezvous with the spies, and obtains the plans. Baroness Von Hulda escapes, but Bob recaptures her and then turns all of the spies over to the authorities. Admiral Wesley expresses his pride in his son, and Bob wins Phyllis Covington, the girl of his heart.