Book excerpt: Superhero Ellie Ultra is given the responsibility of caring for Squeak, the class hamster, for the weekend, which is exciting, but also a little worrying, especially since her dog, Super Fluffy, is too interested in the hamster for comfort--but when she accidentally shrinks herself down to three inches tall Ellie discovers that, even for a superhero, pet sitting is a lot harder when you are no bigger than your pet.