Zagor found out that two foreigners disappeared in the heart of Mato Grosso while they were going to an unknown destination, led by scouts from the Xavante tribe. Could those two be Dexter and Yambo? Zagor and Cico risk their lives, facing the hostile Xavante Indians: according to the Natives, the disappearance of the foreigners is due to some evil spirits of the woods, who seem to live on an inaccessible plateau in the core of the jungle, called Grande Tepui. Will our heroes be able to reach the place? And once there, what horrors are waiting for them?