A crook named Marsden is trying to gain control of the California-Yucatan Railroad. A masked stranger, who gives his name as Zorro, comes to the aid of the railway. In one outlaw raid, railway owner Manuel Vega is mortally wounded. As he lies dying, Zorro reveals himself as Vega's nephew James, whom everyone believes is a weak and spineless coward. But his true nature surges forth to avenge his uncle's death and to save the railroad.