It is Christmas time in South Park. The narrator tells us that the town is being decorated and that people are waiting in long lines for presents because Christmas has to be bought in a store. While out in the forest, the little woodland critters (Squirrely the squirrel, Rabbity the rabbit, Beavery the beaver, and Beary the bear, Porcupiney the porcupine, Skunky the skunk, Foxy the fox, and Deery the deer, Woodpeckery the woodpecker, Mousey the mouse, Racoony the raccoon, and Chickadee-y the chickadee) also prepare for the holiday. Stan (the boy in the red poofball hat) walks in the forest seeing the animals. Mousey finds a problem with their Christmas tree because it does not have a star. The critters think that Stan could help them and he does by making a star out of paper. The critters start singing and dancing so Stan goes home. In the middle of the night, all the critters visit Stan while he is still sleeping and they wake him up. They had received the most magical Christmas gift ever: Porcupiney is pregnant. Porcupiney is a virgin, which means she is going to give birth to their Lord and Savoir. It has been foretold that this would happen but they need a manger for the Savoir to be born in, which is why they came and asked Stan to build one for them. In the forest, Stan builds the manger. When he is done, he decides to leave but stops when he hears a mountain lion. Stan tells it to go away and it does. Squirrely explains to Stan that every year, the mountain lion comes down and eats the animal impregnated with the Savoir. However, this year they put their faith in Stan to go stop the mountain lion.
Stan climbs up the mountain to where it lives. He gets the mountain lion to get out of its cave and it goes after Stan. He tricks the mountain lion to lunge at him and when it did, he moved over and watched as the animal fell to its death over the mountain. Stan is relieved that it is over but at that moment, three little cubs walk up to their dead mother and asked Stan why did he do that. Stan feels guilty for what he did and goes back to the critters (who thought he died). The woodland critters are happy as their Savoir is going to be born, which is the son of Satan, Prince of Darkness. Stan thought they were giving birth to the son of God but they said that only Satan would have sex with a porcupine. To celebrate, the critters sacrifice Rabbity to the devil. They drink his blood and eat his body and then when they are done, they have a blood orgy. Stan is traumatized.
The narrator reviews on what has happened in the story so far. The narrator tries to get Stan to listen to him but Stan does not want to be involved anymore and watches "The Jeffersons" (the remote is broken). Because the narrator was annoying him so much, Stan heads off to the forest to set everything right. When he gets to the forest, the critters have another problem: they need to find a human host body to transfer the Antichrist to after it is born. However, that human must be non-baptized and heathenistic against Christ. Stan cannot be the host because he is not a heathen as he was baptized and is Christian. Squirrely thinks that Stan will help them find a host but he does not. Stan tells them that he is not letting the Antichrist be born and is about to tear down the manger when all the critters use their satanic powers to stop him. Squirrely tells Stan that the only thing that can stop them is a mountain lion and it is dead. Stan remembers the three cubs and climbs the mountain again so he can get their help. The cubs think that Stan came back to kill them. Stan apologizes to the cubs and says that they could help him stop the critters even though they are kids. One cub thinks that they could kill Porcupiney's baby by giving her an abortion. Stan and the narrator get in a fight over what to do next and the narrator wins because Stan and the cubs end up at the abortion clinic. The doctor has many abortions to give since it is Christmas time and he teaches the cubs how to give abortions.
The critters find Kyle and they think it is odd that he is alone on Christmas Eve. Kyle tells them that his family does not celebrate Christmas because they do not believe in Jesus. Since Kyle is Jewish, he was never baptized, making him the perfect host for the Antichrist. The critters take him away. Later, Stan and the three cubs go to the woods to stop the Antichrist from being born. Unfortunately, the Antichrist has already been born when they got there. Just when it looked like Kyle was going to be the host and 10,000 of darkness was about to come, Santa shows up on his sleigh. The critters want to eat his flesh. Santa is disappointed with Stan for helping out the critters. He explains to him that the only way to stop devil-worshiping critters: shoot them. Santa takes out a long shot gun and kills all the critters. As for the Antichrist, it cannot survive without a human host. Kyle then goes and grabs the Antichrist, saying that with his power, he can make the world better for Jews.
It turns out that the whole thing was a story being told by Cartman in school for 'Write Your Own Christmas Story Day'. Kyle knows that the story is just a way for Cartman to rip on him for being Jewish. Mr. Garrison tells Cartman to stop telling the story because if Kyle feels discriminated against, he will get a call from his mother. However, the whole class wants to know the end of the story. Kyle thinks that Santa is just going to end up killing him but Cartman tell him that it will not happen like that. Kyle gives Cartman permission to read the rest of the story: Kyle feels his soul is on fire. Kyle feels sorry for how he acted but Santa tells him he has no choice but to kill him. Stan reminds him of the mountain cubs and they give Kyle an abortion of the ass. The Antichrist comes out and Santa kills it by smashing it with a mallet. Kyle thanks everybody. Santa tells Stan that he has been through a lot and asks if he wants a special present this year. Stan says 'yes' and that present is that Santa to bring the mountain lion back to life. After that, it was the best Christmas ever for 'the boy in the red poofball hat'. Everyone lived happily ever after…………except Kyle who died of AIDS two weeks later.