Third-grader Abby is crazy about animals, but her apartment building won't allow pets. So when Abby gets the chance to look after Mrs. Wilson's two goldfish, Speedy and Slowpoke, she jumps at it. Now she can show her parents that she's responsible enough to have her own pet-sitting business. What could possibly go wrong?

For starters, there's Abby's little sister Tess, who's always tagging along. But what really bugs Abby is the way Tess acts like a dog. When Tess gets them both into trouble, Abby has to think fast. Maybe pet-sitting isn't going to be as easy as she thought.