Secret Service officer Richard Paget receives a letter from his twin brother John imploring him to take over his identity after he commits suicide, so that Richard can subvert the plans made by the airplane company which John had financed, to make defective planes for the United States to use in the war. The company, John's letter relates, is run by German spies. Richard assumes John's identity, enlists in the aviation corps, and goes to France where he is followed by John's fiancée, Lois Graham, a Red Cross nurse. After Richard is shot down over German lines, according to plan, he receives the Iron Cross even though his false information concerning troop movements leads to an Allied victory. Richard marries Lois, but on their wedding night she discovers his Iron Cross, and although she is unable to kill him, she has him arrested. After he turns over German secrets he learned behind enemy lines, and explains his mission, Richard and Lois take off in an airplane for their honeymoon.