Nancy makes the best of not dancing the lead in her ballet school's Deep-Sea Dances show, but becomes jealous when her best friend gets a better role than hers.

When Bean's parents leave her in the care of her older sister Nancy for the afternoon, she enlists her neighbor and best friend Ivy to come over and teach Nancy how to be a really good babysitter.

"Principal Krupp once again turns into the superhero Captain Underpants in order to save the world, and Jerome Horwitz Elementary School, from the evil talking toilets and the Turbo Toilet 2000"-cProvided by publisher.