The film opens in Virginia in 1865, shortly after General Lee's surrender at Battle of Appomattox Court House. A war correspondent Jim Steed exchanges comments with Count Von Bohlen, an arrogant Prussian army officer serving as a military attaché during the American Civil War. A year later Steed is in Vienna shortly before the outbreak of the Austro-Prussian War of 1866. There he encounters a famous dancer, Anna Marie, whom he persuades to spy for him on Von Bohlen, now a member of the Prussian General staff, who has become infatuated with her. However the secret plans which they manage to pass on to the Austrians are unable to prevent the decisive Prussian victory.