The kickball from the fifth novel reaches Uranus and revives the Turbo Toilet 2000, who builds a rocket scooter from the Robo-Plunger's body.

He ends up defeating the Turbo Toilet 2000, but soon, people start interrupting his experiments over trivial things and after a year, Melvin finds Sulu's signal in the future and uses the Robo-Squid suit to take George and Harold back home, before he warns them of bad to come.

After turning Captain Underpants back at Mr. Krupp's, the boys try to nap, but found out that they missed a full school day and their parents force them to do five hours of yard work.

George then realizes they have a test day tomorrow, but in the morning, they fall asleep in their tree house, causing them to get all zeroes.

When Mr. Krupp sees the all teachers naked, and the two Georges and Harolds, he is speechless, and starts repeatedly saying "Buh-buh-bubba-bobba-hob-hubba-hubba-wah-wah" like when he almost married Miss Ribble.