"Treehouse of Horror XV" is a Halloween-themed episode from the sixteenth season of the animated comedy series The Simpsons. It was first broadcast in the United States on the Fox Network on November 7, 2004, the most days after Halloween that any Simpsons Halloween episode was first aired.
In commmon with all previous "Treehouse of Horror" episodes, it is made up of three self-contained stories; "The Ned Zone", "Four Beheadings and a Funeral" and "In the Belly of the Boss". The first story is a parody of the 1979 Stephen King novel The Dead Zone and its movie and TV adaptations. The second story references the Jack the Ripper murders, which took place in the East End of London in 1888, and the Sherlock Holmes stories by Sir Arthur Conan Doyle. The third story is a parody of the 1966 science-fiction movie Fantastic Voyage.
Due to its depiction of drug use (including drugs being taken by the child character Ralph Wiggum) and violence against women, the episode was rated TV-14 in the United States and M (for "mature") in Australia.
The aliens Kang and Kodos star in their own sitcom Keepin' it Kodos. Kodos is preparing dinner for his and Kang's boss, a dinner which consists of all the members of the Simpson family. Their boss enjoys the dinner so much that Kang and Kodos are both given a "hyper-galactic promotion". However, he does not eat the boy Bart Simpson, who is allowed to go free. Bart is sad that the rest of his family have been eaten but Kang and Kodos agree to adopt him.
"The Ned Zone"
Homer Simpson attempts to get a frisbee off a roof by throwing a bowling ball at it. After the bowling ball hits him on the head, the Simpsons' neighbor Ned Flanders is able to see visions of impending death. He is able to accurately predict the manner in which all the people he touches will die. Attempts to prevent the deaths only result in causing them to happen exactly as Ned foresaw them.
Ned has a vision of himself shooting Homer Simpson. Homer finds the idea ridiculous. He hands Ned a gun and continuously taunts him but Ned is unable to bring himself to shoot. Ned is confident that he has stopped one of his predictions from coming true.
Shortly afterwards, Ned has another premonition, in which Homer Simpson, at work in the nuclear power plant, destroys the town of Springfield by pressing the "Core Destruct" button. Ned tries to prevent Homer from going to work. Homer will not be dissuaded because it is the birthday of one of his co-workers and ice cream cake is to be served. Ned races to the nuclear power plant. Over the intercom, he tries to tell Homer not to press the "Core Destruct" button. Unfortunately, static on the intercom makes it sound as if Ned is telling Homer to push the button. In desperation, Ned grabs a security guard's gun and shoots Homer. As Homer falls down dead, his tongue hits the "Core Destruct" button. Both of Ned's premonitions come true and the town of Springfield is completely destroyed.
On arrival in Heaven, Homer Simpson gets his frisbee returned to him by God.
"Four Beheadings and a Funeral"
The story "Four Beheadings and a Funeral" features Lisa and Bart Simpson as Scotland Yard detective Eliza Simpson and her assistant Dr. Bartley.
In London in the year 1890, the Muttonchop Murderer is killing prostitutes with a sword. Eliza Simpson suspects that evil industrialist C. Ebeneezer Burns is the Muttonchop Murderer. Burns is tracked down to an opium den. He is ruled out as a suspect when he says that he has sold all his swords to pay for opium.
Suspicion falls on Homer. He is arrested, tried and sentenced to death. Before Homer is hanged, Eliza Simpson discovers that the chief police officer Inspector Wiggum was the real murderer. Wiggum escapes in a hot air balloon but the balloon is destroyed by the aliens Kang and Kodos, who boast that they have destroyed all of Earth's aircraft.
The entire story is revealed to have just been the dream of the boy Ralph Wiggum, who has been sleeping in an opium den. The story is then revealed to have been a dream within a dream.
"In the Belly of the Boss"
At a science exhibition, Professor Frink demonstrates that he has developed the ability to miniaturize objects and people. The baby Maggie Simpson crawls inside a giant pill, which is then miniaturized and swallowed by Mr. Burns, Homer Simpson's boss. The rest of the Simpson family agree to be miniaturized inside a submarine-like craft to go after her and are injected into Mr. Burns.
The Simpsons retrieve the baby Maggie but then find that the craft cannot carry the weight of all of them on the return journey. Homer Simpson is left behind. The rest of the Simpson family safely leave Mr. Burns' body. Homer Simpson returns to his normal size, while he is still inside Mr. Burns. The episode ends with Homer and Burns leading the rest of the charcaters in a dance to the tune of "I've Got You Under My Skin".