In the 20th anniversary of THE SIMPSONS annual "Treehouse of Horror" Halloween special, three chilling tales of Halloween horror unwind. First, Lisa becomes livid with Miss Hoover, and in a series of homages to classic Hitchcock sets out for deadly revenge. Next, Krusty's latest fast-food sandwich transforms news anchor Kent Brockman into an enraged zombie and twenty-eight days later, cannibal zombies have overrun Springfield. In the final frightening fable, Homer accidentally falls through a trapdoor in Moe's tavern and impales himself on the pipes of Moe's microbrewery. Moe serves the barflies a glass of delicious beer flavored with Homer's blood and Homer, now half-man, half-brewing apparatus, returns for vengeance.

Fed up with Bart's constant pranks, Principal Skinner tells Bart that there is a former Springfield Elementary student hailed as the best prankster ever - even better than Bart - but he won't divulge the legendary student's name. Bart finally gets Groundskeeper Willie to reveal the prankster's identity: Andy Hamilton. Bart tracks down Andy, who is now 19 years old and hasn't grown out of his pranking days. Bart and Andy become fast friends until Bart gets Andy a job working for the ultimate clown.