George and Harold's time-traveling Purple Potty has landed them in a crazy place! The teachers are nice, the cafeteria serves delicious food, and the school principal, Mr. Krupp, thinks they're hilarious. Something is very, very wrong -- and it gets even wronger when the boys' pet pterodactyl, Crackers, and Sulu the Bionic Hamster are captured by George and Harold's evil-twin look-alikes. Now George and Harold must face their greatest foes yet: THEMSELVES! Can they handle this mess on their own, or will they need Captain Underpants to swoop in and save the day?