A Mexican vacation becomes a search for missing Aztec treasure for Scooby-Doo and the gang. The town of Cinco, supposed site of a gala fiesta, is deserted, what with its residents terrorized by a stone monster and the ghost of The Aztec God Of Contezuma. Searching for an ancient pyramid nearby, the gang find clues that lead them to a mysterious river barge and a cave where the treasure is being smuggled away.