Everything goes VERY wrong when George and Harold fall into a parallel universe – and it gets even wronger when they run into their very own evil twins. Now the boys must face their most cunning enemies yet: themselves! And with Captain Underpants facing his own nemesis, the wicked Captain Blunderpants, will good or evil triumph? The fate of the galaxy might all depend on two new superheroes: Great-Granny Girdle and the brave Boxer Boy! Get set for chuckles and adventure in the name of all that is pre-shrunk and cottony – plus even more amazing Flip-o-Rama animation!