Captain Underpants: Captain Underpants and the Sensational Saga of Sir Stinks-A-Lot #12

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 George and Harold's hands!