An unexplored region of Mount M’Boré, in Southern Africa, conceals an incredible secret: the existence of a colony of Dinosaurs, the giant reptiles who populated our planet a hundred million years ago. A rescue expedition , headed by Martin Mystère, goes in search of the explorer Beverly Howard, who has gone missing in this forgotten angle of the World. But the Detective of the Impossible is not alone: there is someone plotting secretly in the background.