As a boy, James Decker courageously defends his disabled friend Almon from the bully Buck Kennon, revealing the sense of justice and fearlessness that later earns him an opportunity to compete for an appointment to West Point. After passing the examinations and enduring the demands of military training, he becomes a young lieutenant at Fort Reno, Arizona, where he joins Maurice Freeman and the scouts Mendez and Cemuri in tracking Geronimo and his Apache followers. Decker and his companions face gunfire, false signals, stealthy reconnaissance, and suspected betrayal by Maroz and Ceballos while attempting to locate the raiders and bring cavalry reinforcements into the pursuit. As the soldiers close in, the danger shifts toward the ranches of the Sutra Valley, and Freeman, riding home without his rifle, sees smoke rising near his family’s dwelling and realizes that the threatened attack may already have begun.