Sir Leonard Wallace, Chief of the Secret Service, sends one of his agents to Germany to obtain vital information from the Baroness von Reudath. Foster is told to feign infatuation with her, but the lines between reality and pretence soon blur as a result of his growing affection for the baroness. Before long, Foster becomes prey to the insane jealousy of the tyrannical Marshal von Strom: Foster suddenly disappears and the baroness is charged with treason - the punishment for which is death. Can Wallace use his cunning to foil von Strom's treacherous plans and rescue the distressed lovers before it's too late?