Texas Ranger Lieutenant Luke Caldwell is leading a detachment of Rangers when they are ambushed by an outlaw gang. After a hard-fought battle, the Rangers defeat the gang, but at the price of several dead and wounded. Among the most severely hurt is Luke, who is sent home by the company surgeon to recuperate. Luke is nearly completely recovered when word comes that his sister’s husband, Hank Brundage, the town marshal of Sonora and Luke’s former riding partner in the Rangers, has been murdered. Luke’s sister was beaten, raped, and left for dead by the same men who murdered her husband. Despite still being on medical leave, Luke heads for Sonora, determined to find the men responsible and bring them to justice.