Mean old Mr. Krupp, headmaster of Jerome Horwitz Elementary School, hates all children, but he especially hates George and Harold. He hates their pranks and their silly giggling and their awful Captain Underpants comic books. One day, Mr. Krupp finally gets the evidence he needs to get his revenge on the boys… their only hope is George's 3-D Hypno-Ring, but what will happen if Captain Underpants really comes to life?!