Geronimo Stilton's ancient ancestor Geronimo Stiltonoot is back in another prehistoric adventure!A visiting rodent has arrived in Old Mouse City with astounding news. On his recent journey to a cold, distant land, he spotted a mountain . . . moving! Holey cheese! Geronimo Stiltonoot is determined to travel to the ice and snow himself to find out what lies behind this mystery. It's a fur-raising expedition!