George and Harold are two imaginative pranksters who make the depressing Jerome Horwitz School a better place. They hypnotize their nemesis, the mean-spirited principal Mr. Krupp. He transforms into the incredibly clueless yet kind-hearted and enthusiastic superhero named Captain Underpants. Even without the mean principal, they discover that having Captain Underpants comes at a steep price. Meanwhile, Professor Poopypants tries to eliminate laughter with the school snitch Melvin, and George and Harold discover that there may be more to Mr. Krupp than they had originally thought.

Navin is an idiot. He grew up in Mississippi as adopted son of a black family but on his 18th birthday he feels he wants to discover the rest of the world and sets out to St. Louis. There everyone exploits his naivety, but then a simple invention brings him a fortune.

When the last day of school comes for a group of students in a philosophy class, their instructor, Mr. Zimit, challenges them to different sorts of exercises that take place in a post-nuclear apocalyptic world. While there, they each get chosen professions and have to decide whether who is valuable or not because the bunker they will be staying in for a year has only enough oxygen for 10 people. Mr. Zimit challenges them in different rounds to see how they could survive. Issues arise when they notice Mr. Zimit is disruptive to the game.

A training exercise for the LAPD SWAT Team goes terribly wrong when they find themselves pitted against two rival gangs while trapped in an abandoned Hangar, armed with nothing but blanks.