Dick Gale, the fun-loving son of a respectable New York lawyer, is given an ultimatum by his father to either get a job or get out. He goes west, and at the border town of Casita, finds Lieutenant George Thorne, a U.S. Cavalry commander, trapped by Landree, an unscrupulous outlaw and killer, who has plundered the villa of Don Sebastián Castanada, one of the old Spanish land-holders, in an attempt to capture his daughter, Mercedes, whom Thorne loves. She has escaped disguised as a peon boy with the help of an Indian, Yaqui, whom she earlier nursed to health. Thorne is injured as he and Dick rescue Mercedes. Afterward, Dick and Mercedes, with Yaqui as their guide, flee into the desert. A sandstorm turns back the villains, their horses are lost, and the Indian guide is injured. Thorne returns to the fort unaware of their plight. They are tracked down by Landree's men; the Yaqui precipitates a landslide, which blocks their path but costs him his life. Thorne rescues the party, and, realizing the love of Dick and Mercedes, relinquishes his own claim on her.