For cavemouse Geronimo Stiltonoot, life is one prehistoric problem after another All the mammoths have fled Old Mouse City It's a total cat-astrophe Not only because mammoths are valuable allies of the cavemice, but also because without them, the cavemice can't make mammoth milkshakes, their delicious national drink. Geronimo Stiltonoot must embark on a daring journey to find the mammoths...and avoid going extinct before he gets back