In early 19th century Mexico the masked swordsman hero Zorro was a champion of the people against the tyranny of Spanish rule, represented by the ruthless Governor Montero. Unfortunately, on the eve of his greatest triumph, the liberation of Mexico, Montero learns of Zorro's secret identity as Don Diego de la Vega and attacks the rebel in his home leaving him imprisoned, his wife dead and his daughter abducted to be claimed as the child of Montero. Twenty years pass, and Montero returns to California intent on a foul plan to bring it under his total control. Upon learning of his return, Don Diego escapes from his long imprisonment and prepares for his revenge. Part of it involves the training of an orphan who helped him as a boy to become his successor. Together, the two must prepare to do battle with Montero and his American henchman to save California and reunite with Diego's lost daughter. So once again, the enemies of freedom and justice in California must fear of the man who leaves the mark of the Z.