Tilman Wagner receives a telegram for help from long-time friend John McCandless Law, an army captain serving at Fort Davis, Texas. John's daughter, Lomida, and the girl's young schoolteacher, Madeline Brown, have fallen into into the hands of Mexican bandits. The leader of the bandits, Chuy Ayala, wants to ransom the girls for the Gatling gun at Ft. Davis, a weapon he needs to begin his revolution.The action intensifies when renegade Indians arrive on the scene. Lomida and Madeline find themselves trapped on the Mexican side of the Rio Grande in an escalating war surrounded by renegades and bandits.Tilman and his friend, Butter, plan to ride into the melee to rescue the girls and return the Gatling gun to its rightful place at Fort Davis, ending Ayala's revolution.