Captain Underpants and the Terrifying Return of Tippy Tinkletrousers

George Beard and Harold Hutchins are 4th graders, best friends, and the co-creators of the comic book company, Treehouse Comix Inc., which, through a series of hilarious events, leads to the turning of Mr. Krupp, their mean old Principal, into his fun, superhero alter ego, Captain Underpants. George, Harold, and Captain Underpants take readers on a fun ride of great adventures through the course of eight books. At the end of the eighth book, George and Harold are escorted away to jail because their evil twins robbed a bank.

When George and Harold are taken off to jail, the boys wonder if things could get any worse. And things to get worse as Tippy Tinkletrousers has returned, and he wants to destroy the world. Tippy is arrested soon and sent to prison, but escapes, taking Mr. Krupp with him. He is aiming to get the better of George and Harold. A large number of events and mishaps lead the readers through the adventures of the characters, and display the interaction between little George and Harold, when they are kindergarteners, five years before the present time.