True story of the dancing team who taught the world to two-step.

Vernon Castle is performing a slapstick routine as "second banana" to vaudevillian Lew Fields when he meets Irene Foote, the daughter of a staid New Rochelle doctor. Irene, who loves to dance, arouses Vernon's ambition to become a great dancer, and she weans him away from vaudeville. After working on dance routines together for three months, they are married and go to Paris under the misconception that they have been hired to perform dance specialties. The Parisian managers, however, only want Vernon to repeat his slapstick act. Irene and Vernon are down to their last franc when they meet Maggie Sutton, an English talent agent who gets them a chance to exhibit their dance, the Castle Walk, at the Cafe de Paris. The Walk is an immediate success, and the Castles' rise to stardom is meteoric. Soon the fashion world is emulating Irene's new hair bob and Vernon's shoes. After many successful tours, they return to the United States to retire and spend quiet hours together. When war breaks out, Vernon, who is British, enlists in the British Flying Service. Many dangerous missions later, he is sent back to the U.S. to teach flying to American aviators. Separated for a long time by the war, the Castles arrange a romantic meeting at a quiet hotel near the air field, and as Irene anxiously awaits the return of her husband, Vernon tragically dies in a plane crash when he swerves to avoid a collision with a student pilot.