Geronimo Stilton 5: The Great Ice Age

When Geronimo's nemeses the Pirate Cats try to travel through time to the year 1889, they accidentally end up in 37993 BC, where they meet their Neanderthal ancestors who tell them about the legend of a Giant Wooly Mammoth, inspiring them to concoct a plan to capture and bring it back to the present; Geronimo must travel to the Ice Age to stop the cats from changing history forever!