In World War I China, Princess Tsu, who leads a secret group dedicated to eradicating German influence in China, learns that the Chinese viceroy, in order to further his own ambitions, has organized an army to help Germany win Russia. She steals their written agreement and smuggles it to American agent Robert Kenyon, with whom she has fallen in love. The princess' jealous fiancé, Prince Kang, tells her that Robert is betrothed to an American girl and, bent on revenge, she informs German agent Von Richtman that Robert possesses the secret papers. In Washington, Von Richtman sends his henchmen to apprehend Robert before he can reach the Secretary of State, but Princess Tsu, whose love of country has triumphed over her personal concerns, foils the plot. Aware of her great love for Prince Kang, she returns to China and marries him.