Kirby Frye, a former Confederate officer but now a Union Cavalry scout, is sent into Montana territory to locate and retrieve three Gatling Guns stolen from the U.S. Arsenal by outlaws believed to have taken them west to sell to the Soiux and Cheyenne. The trail leads him to Red Bluff where, aided by Claire Corville, he and the audience discover together and real quick like that Martin Gavin, a supposedly-honest operator of a freight line, has the guns and intends to exchange them to the Indians for furs..