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.

George and Harold are forced to contemplate a world without Captain Underpants.

When George and Harold use their traveling purple potty to travel to another dimension where the school is nice and the principal, Mr. Krupp, thinks they're funny, they meet up with their evil twins and must face their cleverest enemies ever -- themselves.

Irrepressible friends George and Harold create a new comic book superhero, Super Diaper Baby.

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.

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.

Fourth-grade class clowns George Beard and Harold Hutchins have created the greatest superhero in the history of their elementary school --and now they're going to bring him to life. Meet Captain Underpants, whose true identity is so secret even he doesn't know who he is.

George and Harold, and their doubles, Yesterday George and Yesterday Harold, have a good thing going. Two of them go to school, while the other two hide in the tree house and play video games all day-then they switch! But when their malicious gym teacher, Mr Meaner, creates a method of mind control that turns their fellow students into attentive, obedient, perfect children, the future of all humanity will be in their hands!