A classroom hamster has to be ready for anything, but suddenly there are LOTS-LOTS-LOTS of big surprises in Humphreyas world. Some are exciting, like a new hamster ball. But some are scary, like a run-in with a cat and a new janitor who might be from another planet. But even with all thatas going on, Humphrey finds time to help his classmates with their problems. But will Mrs. Brisbaneas unsqueakable surprise be too much for Humphrey to handle?