For cavemouse Geronimo Stiltonoot, life is one prehistoric problem after another!

All the mammoths of Old Mouse City have mysteriously fled — and it’s a total cat-astrophe! The mammoths are not only valuable allies of the cavemice, but without them, there will be no more mammoth milkshakes, the village’s most delicious national drink.

To save his fellow cavemice, Geronimo must embark on a daring journey to track down the missing mammoths. But with danger lurking around every corner, will he find them in time... or go extinct before he makes it back?