SpongeBob and Patrick are racing to Sandy's Treedome to play. However, the dome has a metal cover over it, and a "KEEP OUT" sign on the door. They go inside the entrance, where they find a television. The television turns on and plays a video, which shows Sandy in a nightgown, eating acorns to store up for the winter. Sandy (on the TV) explains that she is hibernating for the winter. However, when they make too much noise in her room, she suddenly gets up, sleepwalking, and attempts to kill them, believing them to be "Dirty Dan" and "Pinhead Larry," outlaw villains from her dream. However, she soon falls back into her bed, asleep, with Patrick making sure she will not get up again by giving her a pair of earmuffs made from his bellybutton lint.
SpongeBob and Patrick leave her room to play in the snow. They pretend to be Dirty Dan and Pinhead Larry, mocking Sandy, and then begin fighting over which one of them is Dirty Dan. However, the vibrations from them whacking each other with a huge snow shovel (SpongeBob) and a massive baseball bat with a nail through it (Patrick) they knock off the earmuffs, allowing Sandy to hear the ruckus, which alerts Sandy, who comes out of her tree and begins to attack SpongeBob and Patrick. She immediately throws Patrick aside when he is not looking, and then chases SpongeBob until he falls into a pit. SpongeBob tries to throw a small piece of wood at her, but Patrick comes and gets in the way, accidentally taking the hit. He falls into the ditch and then Sandy pounces on them, beats them up, buries them alive, and goes back to bed. As the winter storm grows more intense, SpongeBob and Patrick try to escape, but find that the door is frozen shut.
Unable to survive in the cold weather, they go into Sandy's room and rip off all her fur, SpongeBob makes his share into an "eyebrow/goatee combo" and Patrick fills his pants with the fur he ripped off. SpongeBob proclaims that he is prepared for the "longest, coldest Winter ever!!" However, Winter quickly comes to an end and Sandy wakes up, normal sized. She is surprised to see SpongeBob and Patrick, but soon realizes that they are wearing her fur and she is furless. The last scene shows Sandy drinking lemonade with SpongeBob and Patrick, whose bodies are wrapped around her to make her warm.
According to the Season 2 DVD commentary and in the storyboard, there is a deleted scene where Sandy's bed was hanging from the ceiling, and there was much more saliva/drool. Also stated in commentary, the original title was "Survival of the Morons."
This episode could be taken place after "Prehibernation Week." However, Sandy explained hibernation to SpongeBob in that episode, yet he still does not know what it is in this episode.
It previously snowed in the episode "Christmas Who?"; however, SpongeBob and Patrick act like they have never seen it until this episode, but it could be due to the episodes not being in order.
Sandy's treedome was previously shown during the Winter in "Bubble Buddy." However, oddly, that time she had to go south to survive it, unlike in this episode.
The face that Patrick makes when he says, "Who you callin' Pinhead?" has been parodied countless times over the internet, and has become YouTube's popular meme.
At the end of the episode, when the snow has melted and Sandy first sees SpongeBob and Patrick with her fur, there is no water left in the treedome. However, this does not affect them. Similarly, earlier in the episode, when they were depending on snow for hydration, they are not affected by the lack of snow while inside Sandy's Tree.
In Bahasa Indonesia, in the scene where Sandy is infuriated when SpongeBob and Patrick stole her fur, she grunts rather than mentioning their names (though its airing in Indonesia shows her yell their names out of anger along with grunts).
Also, the scene where Patrick and SpongeBob are attacked by Sandy is rarely shown in Indonesia due to time constraints (as it was aired along with ads) and violence.
In the pilot episode of Fox's drama series Fringe, the beginning of this episode can be seen briefly.
In Arabic, this episode is called "ألم السنجاب ('alam alssanjab)" which means "Squirrel Death."