When Harold and George turn fourth-grade teacher Ms. Ribble into the evil Wedgie Woman, she gives the wedgie of doom to unsuspecting people who stand in her way--including principal-turned-superhero Captain Underpants.

When we last saw our heroes, George and Harold, they had been turned into evil zombie nerds doomed to roam a devastated, post-apocalyptic planet for all eternity. But why, you might ask, didn't the amazing Captain Underpants save the boys from this frightening fate? Because Tippy Tinkletrousers and his time-travelling hijinks prevented George and Harold from creating Captain Underpants in the first place! Now, having changed the course of human history...

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!

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

General Jackrabbit and his Robo-Rabbits from Jupiter attempt to take over the world on Ricky Ricotta's birthday.

Ricky Ricotta, his Mighty Robot, cousin Lucy, and some friends set out to save mousekind from Stupid Stinkbugs from Saturn, with a little help from some special gum and taffy.