Operation F.U.N. is the twenty-seventh episode of Season 5.
After a fun-filled spring break, Timmy and his friends, Chester and A.J., are disappointed that they have to return to school, especially since Mr. Crocker invented a way to write F's with their tears. Cosmo is actually happy that they have to go back to school because of Wanda being a horse and had just pooped in front of him. After Remy visits and tells them about F.U.N. Academy, a school with "no parents, no alarm clocks, fun games and unbelievable food", Timmy wishes for scholarships for him and his friends. Not long after being dropped off by his parents though, Timmy learns that he has been tricked by Remy yet again, and F.U.N. Academy really stands for "For Unruly N'er-do-wells", a military school for troublemakers. Remy had been sent there by his parents but is able to coast through his stay due to bribery, but Timmy and his friends are not so lucky, especially since Timmy's drill sergeant is Shallowgrave, the former truancy officer that lost his job because of a certain "pink-hatted punk"! Remy then traps Cosmo and Wanda with a butterfly net with some missiles and other weapons being pointed at the shack that Timmy's godparents are in. Timmy and his friends must now complete the challenges that Shallowgrave forces them to go through before the missiles and weapons are activated and fired at the shack.
Remy Buxaplenty arrives, Timmy knows about it. Remy is talking about his school. But they arrived at his place, and Remy Buxaplenty captures Cosmo and Wanda with his butterfly net. Then he knows his school training with his teacher and his place. And pass the obstacle course and Remy Still knowing Timmy Turner. But his teacher gets fired and the bullets and missiles destroyed. Timmy and his fairies gave a laugh.