In 1947, the Muroc Army Air Field in California has test pilots fly high-speed aircraft such as the rocket-powered Bell X-1, but some are killed as a result. After another pilot, Slick Goodlin, demands $150,000 to attempt to break the sound barrier, war hero Captain Chuck Yeager receives the chance to fly the X-1. While on a horseback ride with his wife Glennis, Yeager collides with a tree branch and breaks his ribs, which inhibits him from leaning over and locking the door to the X-1. Worried that he might not fly the mission, Yeager confides in friend and fellow pilot Jack Ridley. Ridley cuts off part of a broomstick and tells Yeager to use it as a lever to help seal the hatch to the X-1, and Yeager becomes the first person to fly at supersonic speed, defeating the "demon in the sky".