Ver Cuevana. Capt. Harper's cavalry patrol returns to the fort to find it besieged by Ute Indians. The apparent cause is the recapture of Army traitor Brett Halliday, who deserted to the Utes in a previous war; but Brett has a different story. With capture imminent, the only chance for the surviving men (and one woman) is to boat down a wild, uncharted river, where Harper and Halliday must pull together, like it or not.