Classic western in which the inhabitants of an isolated cavalry fort attempt to escape down the Colorado river after they are besieged by Ute Indians. When Captain Harper (William Talman) and his men return from a patrol they are perturbed to find their fort under siege. They presume the reason for the onslaught to be their capture of Brett Halliday (Dana Andrews), who deserted the army to live with the Utes. Either way, Harper and his men have no choice but to attempt a dangerous escape down the rapids of the Colorado river, with the Utes in hot pursuit.
