The opening sequence is done as a parody of The Munsters, with Homer as Herman Munster, Marge as Lily Munster, Lisa as Marilyn Munster with a book on copyright law, Bart as Eddie Munster, and Abe as Grandpa Munster. Meanwhile, At the front of their mansion, an angry mob of townspeople attack the Munster Simpsons. They stab Marge and Grampa in the chest with stakes, set Homer on fire, and activate a bear trap on Bart's head, leaving Lisa unharmed; she then walks away from the scene while whistling, pretending as if she was never there with no connection of the monstrous family.
In a parody of Ghost Dad, Homer's horoscope says he will die today (and an attractive colleague will compliment him). In turn, Marge's horoscope says her husband will die. Homer dismisses it and leaves for work. On his way there, he narrowly escapes death several times. He is still alive at the end of the day (despite multiple injuries and close calls), but is finally killed after choking on a piece of broccoli, which Dr. Hibbert calls the deadliest vegetable known to man. In Heaven, St. Peter informs Homer that he had not done a good deed in his life, and must perform one within 24 hours before he can officially be let into Heaven. Over the next 24 hours, Homer tries to do good deeds, such as saving Bart from being bullied by Nelson (which only results in Nelson giving Homer a noogie) and helping Principal Skinner's mother, Agnes across the street, which ends up with him dropping her to her death and Homer defending his actions by stating that she was "going to be the next Hitler". With only one minute left, Homer saves an unknown woman's baby in a runaway stroller. Confident, he returns to St. Peter with news of his good deed. Unfortunately, St. Peter did not see Homer perform his good deed as he distracted himself by reading a newspaper. Homer is then sent to Hell, where Satan puts Homer in a headlock and gives him a noogie for all eternity. Homer screams in pain, but Satan tells him to be quiet as he will "wake up John Wayne", who has already woken up for his day in Hell.
In a fairy tale setting, The Simpsons are peasants living in a pumpkin cottage. After Homer lost his job as the village oaf, he abandons Bart and Lisa in the woods to solve the family's food shortage. When Homer returns to the cottage, Marge has him go out looking for the children after admonishing him for throwing them out instead of selling them. Meanwhile, with the help of Lisa's copy of Grimm's Fairy Tales, she and Bart manages to elude the many dangerous creatures in the forest, including a troll-like Moe and the Three Bears (who viciously maul Goldilocks after Bart and Lisa leave the Three Bears' cottage, locking her inside). Meanwhile, Homer has returned to the forest to look for the children, but instead comes across Rapunzel's tower. She asks him to climb up her hair and save her, but Homers weight causes him to accidentally tear off Rapunzels hair from her scalp, and he hides it in some nearby bushes before leaving. The siblings eventually come seek shelter in a gingerbread house owned by a witch. Lisa is wary as it is exactly like the story "Hansel and Gretel", but Bart decides to trust her, only for the children to be captured, with Lisa being forced to clean the witch's house and Bart being fed candy and pastries to fatten him up for eating, which Lisa tries to point out to him, though Bart doesn't care and even bastes himself with a turkey baster. The kids asks the witch why she even bothers having Lisa clean the house as she lives alone with no friends. The witch denies this, saying she has a boyfriend with the fake-sounding name "George Cauldron", which the kids laugh at. Angered, the witch tries to force Lisa into the oven after she scoffs at the made-up boyfriend. Just then, Homer eats his way through the gingerbread house's walls to save the children, resulting in the witch turning him into a half-chicken, half-fish creature with donkey ears and broom-arms. The witch then tries to shove Homer into the oven, only to be overpowered and shoved inside the oven herself, roasting her to death. Surprisingly, a handsome man then shows up at the door and identifies himself as George Cauldron, asking Homer, Bart, and Lisa if they have seen a woman named Suzanne. Homer remarks that "she'll be ready in twenty minutes", turning up the oven; Cauldron complains that "the concert's at eight pm". The peasant Simpsons are reunited, and are now living happily ever after with a mostly restored Homer still having a chicken's half-body as he produces eggs for the family.
In a parody of The Day of the Dolphin, Lisa takes pity on the star attraction of Springfield's Marine World, a dolphin named Snorky, whose trainers let him be humiliated while forced to perform stunts for the crowd's amusement. After Snorky's show, Lisa sets the dolphin free to swim in the ocean. Unbeknownst to Lisa, Snorky is actually king of the dolphins and organizes the world's dolphins into an army to declare war on humanity. The dolphins attack Springfield, first killing Lenny during his night swim and then the Sea Captain (who claims he can stop them) before marching towards the town on their tails. During the town meeting, Snorky takes the stage and reveals he is capable of speaking. Snorky tells Springfield that dolphins used to live on land but were banished to the ocean by humans. Now the dolphins want to banish all mankind to live in the sea. The humans refuse to submit to the dolphins' will without a fight, only to find the dolphins greatly outnumber them. When Lisa is bitten by a small dolphin after removing a set of bottle rings from around its face, Homer encourages the townspeople to fight back. A battle ensues between the dolphins and the humans, with heavy casualties on both sides. The end of the story reveals the human lost the war and have been driven into the sea. Lisa admits she regrets freeing Snorky in the first place, but Marge comforts her that everyone will have to adjust to their new life as marine animals. A drowned Krusty the Clown floats near Marge. In disgust, she kicks it away, where it floats into dozens of other corpses, which spell out "The End?".
Meanwhile, after the final story ended. the two aliens Kang and Kodos complain that they have been left out of the Simpsons Halloween special, until they get an offer to do commercials for Old Navy which they plan to accept.