When George and Harold hypnotize their principal into thinking that he is the superhero Captain Underpants, he leads them to the lair of the nefarious Dr. Diaper, where they must defeat his evil robot henchmen.

George and Harold -- Tree House Comix, Inc. -- The Adventures of Captain Underpants -- Mean Old Mr. Krupp -- One Day Very, Very Soon -- Busted -- A Little Blackmail -- Crime and Punishment -- Four-to-Six Weeks Later -- The 3-D Hypno-Ring -- Fun with Hypnosis -- Out the Window -- Bank Robbers -- The Big Bang -- Dr. Diaper -- The Extremely Graphic Violence Chapter (in Flip-O-Rama) -- The Escape -- To Make a Long Story Short -- Back to School -- The End? -- .