Mexican freedom fighters loyal to Benito Juárez take over the Ponderosa, gravely wound Little Joe, and force Ben to guide them to a wagon train loaded with gold being smuggled to California by Emperor Maximilian. General Diaz, a Mexican patriot, steals gold shipments to finance his attacks against Emperor Maximillian. Ben is taken hostage to help with the robbery of a gold wagon, and Joe is shot in the back by one of Diaz's unethical henchmen, Forsythe. Ben comes to respect the general's sincerity.