When Geronimo accompanies his nephew's class to Niagara Falls, he is surrounded by mischievous young mouselets who seem determines to send him over the Falls in a barrel!

The Pirate Cats, Geronimo's worst enemies, have discovered a way to travel back in time, and when they find themselves in the middle of the Ice Age, they decide to capture a great wolly mammoth and bring it back to the present! Can Geronimo and his gang stop this crazy scheme?