For cavemouse Geronimo Stiltonoot, life is one prehistoric problem after another! Geronimo Stiltonoot and friends have been invited to participate in a Stone Age treasure hunt! How fun! The one issue is that it has been set up by Gossip Radio host Sally Rockmousen, Geronimo's rival. Is it some sort of trick? The hunt is full of difficult riddles and very stinky dinosaurs... but nothing will stop Geronimo's team!