U.S. Cavalry trooper Dan Parker is asked by Major Cooper to catch a Nevada rustler known as "Black Jack." He does, but then is double-crossed and shot by a fellow soldier, Lt. Burke, who is in cahoots with the thief.
Not knowing about Burke's deceit, the major sends him to California to investigate a land swindler, Sam Casey. It turns out Casey is pretending to be "Black Jack" and is part of the Jesse James outlaw gang. Parker recovers from his gunshot wound and leaves for California, where his father owns a ranch.
Casey, helped by hired gun Ace Harkey and a crooked sheriff, is trying to move a half-million dollars in stolen gold. His honest secretary, Rita Starr, tries to inform the law, but Dan's dad is killed. Burke objects to Casey's methods and is also murdered. Dan shoots it out with Casey, is victorious and stays in town, retiring from the Cavalry, to settle down with Rita.
