Can you show a summary of Captain Underpants?

George Beard and Harold Hutchins are really mischievous students in fourth grade of Jerome Horwitz Elementary School. They once did many things like putting helium in the football and putting soap bubble in the bleachers' trumpets to ruin the school's football game. Unfortunately, Mr. Krupp, an angry principal of Jerome Horwitz, had caught them on tape, and threatened to give the tape to the football team unless they served him for the rest of their lives. George and Harold ordered a hypnotizing ring to hypnotize Mr. Krupp, and they had a lot of fun with him, until they told him to pretend to be Captain Underpants. He then took off his clothes and went out. From then on, if you snap your fingers near Mr. Krupp, he'll turn into Captain Underpants, and if water touches Captain Underpants, he'll immediately turn back into Mr. Krupp. If you haven't bought the books, I'm sure you'll enjoy them.