A spoof on 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. At the front of their mansion, an angry mob of townspeople confront the Simpsons. They stab Marge and Grampa, set Homer on fire, and set a leghold trap on Bart. Then they shower off, leaving Lisa alone, who runs away in fear. The intro was done in black-and-white and the Simpsons theme was done similar to the theme of The Munsters.

Homer's horoscope says he will die that day. He dismisses it and leaves for work, narrowly escaping death several times on the way there. He is still alive at the end of the day, but is finally killed by a piece of broccoli. 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, although this is reduced to 23 hours when he re-eats the broccoli that killed him and re-dies.

Over the next 24 hours, Homer tries to do good deeds, such as saving Bart from being bullied by Nelson 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 a 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 manage 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. 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 is too busy eating treats to care. Lisa tries to stall the witch by claiming she is lonely. The witch denies this, claiming she has a boyfriend named "George Cauldron". When Lisa scoffs at this, the witch attempts to throw her into the oven, but Homer arrives to save the children, eating his way through the gingerbread house's walls.

The witch turns Homer into a half-chicken, half-fish creature with donkey ears and broom-arms. She then tries to shove him into the oven, only for Homer to overpower and shove her to her death in the oven, before George Cauldron comes to the door. The Simpsons are reunited, and are now living happily ever after with a mostly restored Homer still having a chicken's lower body as he produces eggs for the family, meaning that they will never go hungry again.

In a parody of The Day of the Dolphin and The Birds, 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 whiskey-soaked night swim ("alcohol and nightswimming: it's a winning combination") 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 underwater. 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 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 humans 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". As Marge says this, several corpses, including Krusty the Clown, floating past form the words "The End?" nearby, much to her disgust and sadness.

After the last story, the two aliens, Kang and Kodos, complain that they have been left out of the Halloween special. Suddenly, they receive a phone call from Old Navy, asking if the Rigellians can do a commercial, which they accept.