Dave Harmon, a contract freighter for the Army, must deliver an important shipment of rifles across the desert to Fort Whipple. A small group of army officers accompany Harmon's wagon train to guard against Apaches and marauding outlaws. Harmon learns that one of the men, Brick Noonan, has arranged an ambush along the trail, so that the latter can sell the rifles for his own profit. Harmon eventually turns the tables on Noonan's waiting men, thereby thwarting the ambush and killing Noonan in the process. With this obstacle removed, Harmon successfully delivers the guns to Fort Whipple.