When George and Harold hypnotize their principal into thinking that he is the superhero Captain Underpants, he leads them to the lair of the nefarious Dr. Diaper, where they must defeat his evil robot henchmen.
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.
In his first journal, middle schooler Rowley Jefferson, Greg Heffley's sidekick, records his experiences and misguided decision to write a biography of Greg, who, in his own mind, is destined to become rich and famous.
A snotty situation ensues when Melvin Sneedley, an academically-gifted student, turns into the Bionic Booger Boy and must be stopped by George, Harold, and Captain Underpants. By flipping the pages, the reader may view a...