The film begins in 1947 at the Muroc Army Air Field in California, with civilian and military test pilots flight-testing high-speed aircraft, including the rocket-powered Bell X-1. Death is a part of their life. After privateer Slick Goodlin demands $150,000 () to attempt to break the sound barrier in the X1, World War II hero Captain Chuck Yeager is given the chance. While horseback riding with his wife, Glennis, the evening before his historic flight, Yeager falls and breaks his ribs, an injury which inhibits his ability to lock the door on the X-1. Worried that he might not fly the secret mission, he confides in friend and fellow pilot Jack Ridley, who solves the problem by giving Yeager the stump of a broom handle to use as leverage. Though the X1 bucks like a wild bronco, and pushes him to his limit, Yeager goes supersonic and lives. Yet the attendant sonic boom initially causes people to think his plane has exploded. However, an officer immediately classifies his achievement, denying him the fame of his accomplishment, which some people thought couldn't be done in an airplane.