Union Army Captain Roper watches over Fort Bravo, a camp in Arizona filled with Confederate rebels. Its isolated position and unfriendly natives make escape almost impossible. Some try nevertheless, but are always brought back by by-the-book officer Roper.
When prisoner Bailey escapes he is brought back with a noose around his neck by Roper. Roper wants to show any of the others that the same fate awaits them if they dare attempt to flee. As a result his commanding officer, Owens, takes Roper to task, and his compatriots will have nothing to do with him because of his cruelty.
But Roper feels that discipline must be maintained, and defends his behavior.
Blonde and beautiful Carla Forester arrives at the fort to attend the wedding of Owens’ daughter who is to marry Lt. Beecher. She is actually a southern agent whose job is to aid the rebels and their leader, Capt. John Marsh, in an escape. She begins to seduce Roper and learns that he is not as bad as she thought. She departs with the escaping rebels, but Roper soon pursues and eventually catches up with them. He engages in a hand-to-hand battle with Marsh who is also in love with Carla. Roper leads the captured men back to the fort, but they are waylaid by hostile Indians.