Hopalong Cassidy (William Boyd), boss of the Bar 20 ranch in Texas, rides down the Camino Real in the New Mexico cattle country near Alamogordo, in response to an urgent message from his lifelong sweetheart, Nora Blake (Nora Lane), who is in serious trouble. Before he and his saddlemates, "Lucky" Jenkins (Russell Hayden) and "Pappy (Frank Darien), can reach her ranch, they are stopped by Clay Allison ('Robert Fiske (I)' qv), a cattle-rustler who is in almost complete control of the district, and wants to extend his holdings by seizing Nora's cattle and driving her out. Seeing Cassidy as a menace to his plans, he has him arrested on a trumped-up charge. Cassidy and his pals shoot their way out of the trouble and reach Nora;s ranch where they learn that Allison's henchmen have murdered her foreman, Tom Dillon (Jack Elliott), and Allison has sent for a crew of outlaws on the Texas border.