When Professor Pippy P. Poopypants comes to Jerome Horwitz Elementary School to teach science, and he goes off the deep end because students make fun of his name, only Captain Underpants can save the school from the professor's perilous plot.

Hubie has been sent to the principal's office. Is she really the monster he has heard about?

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

Harold and George's time-traveling Purple Potty lands them in an alternate universe where everything seems delightful, but evil lurks just beneath the surface, and leads to a battle between Captain Underpants and his own evil twin.

"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"--

When a principal loves his school so much that he wants the children to attend classes every day of the year, it's up to his students to show him free time is a good thing, too.

Only Captain Underpants can stop the three evil space aliens who have invaded Jerome Horwitz Elementary School and turned everyone into lunchroom zombie nerds.

George and Harold have really done it this time-- they've created a monster! She's faster, smarter, and more evil than anything the world has seen before--she's Wedgie Woman! With the help of her horrible robots and her horrendous hairdo, Wedgie Woman is on a mission to take over the world, and she'll give a whopping wedgie to anyone who stands in her way--including Captain Underpants.

When the new vice principal is put in charge of Ella Mentry School for a few days, she tries out some very unusual ideas about how students learn.

When the teachers of Ella Mentry School go on strike, A. J. and the gang meet a new principal who does not believe in rules and says that the students do not have to learn anything if they do not want to.