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

Principal Krupp becomes the superhero Captain Underpants in order to save the world and his school from the Turbo Toilet 2000.

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.

In trouble with their principal because of their comic books about poop, George and Harold decide to create a new graphic novel about an entirely different subject: pee.

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, 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!

Whenever Dragon wakes up groggy, he always does everything wrong, like sweeping a hole in his dirt floor, or reading an egg and frying his newspaper.

While sitting in detention, George and Harold accidentally create an army of evil talking toilets, and Principal Krupp's alter ego, Captain Underpants, has to save the world from it. Includes CD-ROM.

Principal Krupp, in the guise of his alter ego Captain Underpants, tries to come to the rescue when three evil space aliens infiltrate Jerome Horwitz Elementary School and turn everyone into lunchroom zombie nerds.