The Rough Riders discover a Union prison camp which still holds Confederate POWs. It seems that the prison commandant has doctored the camp records so that he can still keep the former Confederates prisoner, even though the war is over. The three try to come up with a plan to free the prisoners.
Flagg, Kirby and Sinclair are bushwhacked in the middle of the scrub lands by a desperadoes, then their horses taken by indians. Sergeant Sinclair is the least injured, and goes on a long, grueling trek across the badlands, fighting off more indians and finally catching up to the gang.