While waiting in a hotel lobby for instructions from his government, Ludwig Schumann, an agent of the Black Legion, is enchanted by Marion Washburn, the daughter of a Texas senator. As he is about to speak to the girl, Schumann is stunned to see a young American enter who could be his double. The American is James Walbert, whom Schumann's contact mistakes for the agent. The contact passes to Walbert a photograph of a woman spy, Wanda Bartell, whom the agent is to meet aboard a steamer. Walbert realizes the mistake and determines to protect his country. After overpowering Schumann, Walbert rushes to the steamer where he meets Wanda. Also aboard are Marion and her fiancé, Herbert Cornell, a Washington fop who is trying to prove his earnestness by transporting secret plans to New York. Arriving in New York, Wanda and Walbert report to the Black Legion headquarters where they are instructed to procure Cornell's plans. Wanda succeeds in drugging Cornell, but Walbert intervenes, seizes the plans and returns to headquarters, intent upon smashing the organization. He is greeted by Schumann, who has exposed the spy, and is hopelessly outnumbered until the police arrive, having been summoned by Marion.