Texas Rangers Jack Carson and Eddie Brand have been hunting outlaw Lope Gamboa for some time without success, but when they ride into Yuma it seems their luck has changed. An assignment of US gold is to be transported along the Oxbow route by Conestoga wagon and the Rangers are convinced that Gamboa will attempt to steal the gold. As all factions close in on the lumbering Conestoga wagon, the trail leads inexorably to a bloody climax in the Gila desert...