In the ending of “Captain Underpants: The First Epic Movie,” George Beard and Harold Hutchins use the Hypno-Ring to transform their principal, Mr. Krupp, into the superhero they created in their comics, Captain Underpants. Unaware of his dual identity, Captain Underpants becomes the new principal at Jerome Horwitz Elementary School.
Throughout the film, Captain Underpants faces off against the villainous Professor Poopypants, who wants to rid the world of laughter. The climax involves a battle between Captain Underpants and Professor Poopypants, with George and Harold helping their superhero with clever strategies.
In a twist, the film introduces the Turbo Toilet 2000, a creation from George and Harold’s comics brought to life by the Hypno-Ring. The Turbo Toilet 2000 becomes a monstrous threat, but Captain Underpants defeats it with the help of George, Harold, and a giant inflatable bouncy house.
In the end, Mr. Krupp retains no memory of being Captain Underpants, and George and Harold continue their friendship and love for creating comics. The film concludes with the suggestion that more adventures may await the characters in future Captain Underpants stories.