During spring break, archaeology students Adam Andrews and Eva Lunes fly to the Yucatan to research Mayan pyramids, ruins and myths. When their island guide, Enrique, offers to give them a private tour of Kukulkan's Island, also called Snake Island, they seize the opportunity, as it has some of the most fantastic, least-seen ruins of all Mayan culture. When Eva and Adam arrive at Snake Island, they tour Kukulkan's Pyramid and learn of the legend of the Forbidden Tree and its cursed fruit. Adam and Eva also run into a mysterious man who warns them to get off the island. Instead of escaping, they become trapped in a chamber of unspeakable horrors, where they discover evidence of recent human sacrifices. When they become prisoners of a thriving savage cult, Eva is eyed as the perfect sacrifice to the Serpent God.