At West Point Military Academy in 1854, cadet Carl Rader (Van Heflin), an agent of John Brown, is dishonorably discharged for distributing anti-slavery pamphlets. His classmates Jeb Stuart (Errol Flynn) and George Custer (Ronald Reagan) become second lieutenants and are posted to Fort Leavenworth, Kansas Territory, the most dangerous duty in the Army—an assignment they relish. On the way to Kansas, Custer and Stuart meet Cyrus K. Holliday, in charge of building the railroad to Santa Fe, New Mexico, and his daughter Kit (Olivia de Havilland), with whom both officers fall in love.