The mysterious Don Del Oro ("Lord of Gold"), an idol of the Yaqui Indians, has emerged and attacks the gold trade of the Republic of Mexico, planning to take over the land and become Emperor. A man named Francisco is put in charge of a fighting legion to combat the Yaqui tribe and protect the gold, but he is attacked by men working for Don Del Oro. Zorro comes to his rescue, but it is too late for him. Francisco's partner recognizes Zorro as the hidalgo Don Diego Vega. Francisco asks Diego, as Zorro, to take over the fighting legion and defeat Don Del Oro.