 The traveling Frenchman Foucard impresses the pueblo, even ever-skeptic Don Diego, as magician and pickpocket, then romances Victoria and performs various science-based services to various villagers. Sergeant Mendoza must command the protection of a gold shipment, but as earlier near San Francisco, it is robbed by someone who uses a fireball. Even Zorro was too late and finds Foucard asleep, from a distance. Diego shows Felipe the chemical properties of pyrosulphate solve two of Foucard s mysteries: how the magician  revived  an apparently dead dove and how the thief made a fireball explode. Zorro is just in time, after carefully searching his room, to stop Foucard from kidnapping his  beloved  Victoria at sword-point...