Todd finds the Book of Pure Evil and uses it to become a better guitar player in an attempt to win his dream girl Jenny away from her douche-bag boyfriend. But along with making him a better guitar player, it also turns Todd evil.
Hannah uses the book to create a homunculus as a science project for the upcoming science fair, but the creature, which for some reason looks like Todd, breaks free. Todd, Curtis, Jenny and Hannah form a gang to stop the book.
A goth girl named Marcy uses the book to summon her favorite rock stars from the dead, but the zombie rock stars eat her parents and she's forced to keep them in her basement and feeds them with guys that she lures over to her house.
A bullied gay student at Crowley High uses the book to make every other guy at school gay, including Todd and Curtis, while making himself straight. Atticus attempts to glimpse Todd's penis to try and find the mark of the Pure Evil One.
The fattest girl in school uses the book to become skinny, but her leftover fat creates a monster that turns all the other girls in the school fat. Jenny becomes fat and Todd has to prove to her that his feelings for her aren't shallow.
A slow-witted student uses the book to become the smartest kid in school, so the book creates a "stupid smoke" that makes everyone who breathes it stupid except for him, much to the amusement of stoners Curtis and Todd.
Jenny begins a lesbian relationship, causing the girl's jealous twin sister to use the book, creating clones armies of the sisters who battle it out in the school hallways. Hannah creates Todd a special suit so he can sense Pure Evil.
A bully with a small penis is enraged when Todd sends a picture of it around the school. He uses the book to give himself a mammoth member, which goes out of control and starts turning anyone who looks at it to stone, starting with Curtis.
A girl uses the book to get pregnant, but the book accelerates the pregnancy, ending in a giant baby wreaking havoc in the halls of the school. Todd tries to reason with the baby and prove to Jenny that he could be a good father.
A basketball player uses the book and gets possessed by a ghost from the 1950's, causing him and Jenny to fall for each other. He challenges Todd to a suicidal drag race for Jenny's heart, for which the gang soups up Atticus' van.
A girl uses the book to become a better singer, but the spell backfires and her tongue falls out. She becomes the Phantom of Crowley High and Curtis falls for her. Meanwhile Atticus, Todd, and Jenny try to whip up a heavy metal musical.
A genius chess player gets his hands on the book and forms a bizarre cult in the chessnasium, convinced that Todd is the Pure Evil One come to bring about the apocalypse. The cult tries to lure Todd into a trap to destroy him.
Curtis uses the book to give himself a new giant evil arm. Todd must face the truth about his evil destiny as he fights Curtis, and Jenny learns the truth about her father. Atticus tries to regain his place among the Satanists.