In Paris, before America's entrance into World War I, Marion Ashley discovers that her husband, Franz Jorn, is a German spy and she leaves him to live with her father, the American ambassador to the neutral kingdom of Belmark. Later, Marion, having heard that her husband was killed in Paris, happily accepts the marriage proposal of the Crown Prince of Belmark, although their marriage is kept a secret. The German chancellor proposes a marriage between the prince and a German princess but the prince refuses, even after the chancellor produces Jorn, who had escaped Paris and fled to Germany. Word comes that the United States has entered the war and a bomb explodes in the palace, injuring Marion and killing Jorn. Belmark sides with the Allies, and Marion and the prince renew their vows.