Captain Underpants, the former school principal turned crime-fighting, wedgie-dodging superhero, uses his wacky talents to outwit the evil Dr. Diaper. By the author of the Dumb Bunnies series. Simultaneous." 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.

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

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.

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!