The long-buried sins of a foster father return to haunt a younger generation in Mexican director Arturo Martinez, Sr.'s 1965 Spanish-language western Un Hombre Peligroso. Rodolfo de Anda stars as the gunfighter El Zurdo, nicknamed 'Lefty.' During his younger days, El Zurdo was forced to murder a gambler in self-defense. He subsequently adopted the gambler's orphaned son, Mario, but consciously avoided informing the child of the circumstances. Years later, as Mario comes of age, he discovers the truth, craves vengeance for his father's death, and decides to square off in a duel against El Zurdo.