Marge gives a warning about the episode and says that they're not allowed to air it. Instead, they air a clip from the movie 200 Miles to Oregon. The clip is cut off by Bart's voice who starts to give an ominous message. Homer cuts in and ruins the mood. Bart then introduces The Simpsons Halloween Special.

The camera pans through the Springfield Cemetery, showing Moe getting hanged, Patty and Selma being burned as witches, and several adults having their heads cut off by Bart.

In a parody of The Shining, the family gets invited to Mr. Burns' summer cottage to look after it while he goes away. While outside, Bart starts to annoy Willie and reads his thoughts. Willie tells him that he has the shinning and says he should use it to call him if his dad starts to go loopy. Mr. Burns and Smithers cut the cable and take all the beer away, causing Homer to go crazy. He goes to the bar where Moe, as a ghost, tells him he'll give him a beer if he murders his family. Bart calls Willie to help, but Willie gets an axe in the back by Homer. Homer is ready to kill them until Lisa finds Willie's mini-TV in the snow. Homer calls his family to sit in the snow with him and they freeze while watching.

For some unexplained reason, Homer gets his hand jammed in the toaster, and breaks it trying to get it off. Homer attempts to fix it, and the modifications to the toaster turn it into a time machine. Homer travels back to the time of the dinosaurs, but realizes that touching anything will impact the future. When he kills a mosquito, he returns to find that Flanders is the unquestioned lord and master of the world.

He goes back to the time of the dinosaurs in hopes to change the future, back and ends up killing a fish. He returns only to find that Bart and Lisa are giants.

His third attempt to change the past succeeds in him wiping out all the dinosaurs by sneezing. His return to the present presents him with a perfect family, along with the news that they own a Lexus and that Patty and Selma are dead. Homer is content until he asks Marge for a donut: something she's never heard of. Homer flees the new timeline in terror, before donuts begin to rain down from the sky.

Now completely upset, Homer goes on a rampage and destroys anything in the past that he can. The future ends up changing multiple times, before Homer finally stops and returns to the present. Everything appears to be normal, until the family start eating a meal with their lizard tongues. Homer decides it is close enough.

At Springfield Elementary School, the class is playing around. Bart then decides that the class should all turns their desks backwards as a prank. However, only Bart does this, causing him to get detention. Since the detention room is full, Bart is sent to the cafeteria instead. When Jimbo trips up Lunchlady Doris and a pot of sauce, he gets covered in it. Principal Skinner tastes Jimbo and finds him delicious, so he sends Jimbo to help Lunchlady Doris in the kitchen. Jimbo is then cooked and turned into burgers, which the staff find delicious. The next day, ter cuts in line to get more food. He is then sent to detention and also turned into food, which is served the next day. Lisa finds it weird that kids are disappearing and then food named after them is being served. She and Bart go to Marge and ask for help. However, Marge refuses to help, saying that they are old enough to fight their own battles.

Soon, only a handful of students are left and are merged into one class. Bart, Lisa, and Milhouse decide to escape the classroom, but are then chased by the school's staff. As Willie tries to rescue them, he is axed in the back by Skinner, killing him. The kids end up in the blender room where Milhouse falls in. as Bart and Lisa talk about how something will save them, they also fall into the blender.

Bart wakes up to find this was all a dream, but a mysterious fog seeps in through the window, turning the family (and Willie) inside out. They all begin to do a musical number about being turned inside out, at the end of which Santa's Little Helper drags Bart offstage.