Bundle up in your thickest furs for a chilling prehistoric adventure! Geronimo Stilton's ancient ancestor, Geronimo Stiltonoot, is living a quiet life in the Stone Age until some astounding news rocks Old Mouse City. A visiting traveler reveals that in a distant, freezing land, an entire mountain has been spotted moving! Holey cheese! You must join Geronimo Stiltonoot as he bravely packs his bags and sets off on a perilous trip into the ice and snow to solve this massive mystery. What kind of enormous creature could possibly look like a walking mountain? You will face freezing winds, slippery ice, and hilarious prehistoric challenges along the way. This fur-raising expedition is packed with over-the-top silliness and lightning-fast action. Grab this exciting chapter book and prepare for a wonderfully wacky journey back in time!