"Friends and pranking partners Miles and Niles face a tough challenge when their favorite goat and nemesis, Principal Barkin, is replaced by his stern, no-nonsense father, Former Principal Barkin, who turns the school into boot camp"--

The monstrous Turbo Toilet 2000 is determined to take revenge on George, Harold, and Captain Underpants.

It's Thanksgiving, but the kids at Ella Mentry School aren't feeling very thankful because Dr. Carbles is grumpier than ever and wants to fire Mr. Klutz. It is up to A.J. and his friends to save their principal's job.

The Notebook of Doom is missing and Alexander and his fellow-monster hunters, Rip and Nikki, are convinced that the boss-monster has it; but is that monster the mysterious Principal Vanderpants, who is certainly behaving oddly, or someone else--and they need to figure that out quickly because a mistake could have deadly consequences for Stermont Elementary.

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 animated illustrations.

A skateboarding principal offers unusual incentives to his students to motivate them to learn more. Principal Klutz was hanging upside down from the school flagpole! He kissed a pig on the lips! He painted his bald head orange! And now he wants to bungee-jump off the roof of the school, dressed like Santa Claus! In fact, all the grown-ups at A.J.'s school seem to have something wrong with them. What's going on here? What are A.J. and the kids in his...

While Raven is away, Luca breaks his promise to her and returns to the Wish Library, asking to be in charge at school, but being principal for a day is not all fun and games.

George, Harold, Captain Underpants, and Sulu the bionic hamster battle the three ridiculous Robo-Boogers in an attempt to turn the Bionic Booger Boy back into Melvin Sneedly.

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.

"There's a new principal at Ella Mentry School. Yes, it's true! Mr. Klutz is retiring and the president of the Board of Education, Dr. Carbles (Boo! Hiss!), has hired the best person for the job -- or at least the funniest. But stand-up comedian Mrs. Stoker will have to face Vice Principal Mrs. Jafee in a big joke-off duel to defend her new job. Will Mrs. Stoker have the last laugh? Or will shoe lose her audience when things get serious?"--