Also known as: "Duel at the Rio Grande" and 'Il Segno di Zorro'. The son of a Spanish aristocrat lady discovers that he has a father living in Mexico. The father has requested the help of his son with some trouble at hand. Reluctantly, the son sails across the Atlantic only to find his father murdered by the evil local administration. Revenge follows. Starring Sean Flynn, Armando Calvo, Folco Lulli, Gaby Andre, and others. Directed by Mario Caiano.