Oscar, Arabella, and their friends can't wait to begin their second termat theMammoth Academy. But when they arrive at school on the first day after winter break, there's a threatening graffiti message waiting for them. It seems the Cave Skool has moved nearby, and its pupils—those wild and dangerous animals called humans —are wreaking havoc. When a huge snowstorm hits and everyone is trapped inside the academy, the humans attack! With a little teamwork and a lot of explosive materials, the mammoths and their friends just might be able to save the day.