Cisco and Pancho, enroute to visit Mama Maria, lose their way in a sandstorm and pass out. When they recover they find themselves in a beautiful hidden valley saved by Nedra who insist they are in grave danger and should leave quickly. But before they can do so, Cahllis and Bardi find them and insist they remain as guests. But Cisco senses something is drastically wrong. Cisco and Pancho learn that Challis is conducting piracy against wagon trains which are led into Hidden Valley and looted while the men are forced into peonage.