The plot revolves around a rivalry between sand-hog "Hard Rock" Harrigan (O'Brien) and his foreman Black Jack Riley. At the center of their conflict is their mutual affection for heroine "Andy" Anderson (Irene Hervey). But when the chips are down and Riley is trapped in a tunnel cave-in, it is Harrigan who comes to the rescue.

Running from the law, Jim Hall joins Hays’ gang. Hays is foreman on the Herrick ranch and plans to rustle Herrick’s cattle. Attracted to Herrick’s sister Helen, Jim decides to tell the Sheriff about the raid. But when his plan is overheard he is made a prisoner.

Expelled from his lieutenancy in the Marine Corps, Bill Traylor reenlists as a private. His unit is sent to a Latin American country where a rebel leader called The Torch promotes insurrection. There Traylor encounters again Captain Benton, the man responsible for his disgrace and his rival for the love of a girl.

Gangster Chandler and his accomplice Tracy arrive at a dude ranch. Cowboy Kentucky arrives at the same time. When Tracy double-crosses his boss and has the stage robbed, Kentucky finds the outlaws and brings them in. Tracy frames him for the murder of the driver but his pal Cactus gets him out of jail. He returns just as Chandler shoots Tracy and Kentucky finds himself arrested for another murder.

A boxer is killed in the ring, and the only clue is a tune that a man was whistling.