Hands out its annual Halloween treats on the "Treehouse of Horror XV" special featuring three deliciously frightful mini-episodes. In "The Ned Zone," Ned Flanders gains the power of foretelling people's deaths after suffering a head injury, and is shocked to discover that he will be the one to kill Homer. In the second short, "In the Belly of the Boss," Maggie is shrunken inside a vitamin capsule in a freak science accident and is swallowed by Mr. Burns. The final Halloween scare, "Four Beheadings and a Funeral," is set in Victorian London, where Master Detective Eliza Simpson and her faithful sidekick, Dr. Bartley, attempt to catch The Muttonchop Murderer, a Jack the Ripper-esque serial killer.

Feeling unappreciated by her own children, Marge takes in neglected son and Springfield Elementary School bully Nelson Muntz. Horrified his tormentor is now living under the same roof, Bart goes on a mission to find Nelson's parents and reunite the Muntzes.