The buddies go to the control room ("heart") of Smileyland to fix their planet after it is inadvertently destroyed.
The show's Theme Song plays, but Kaeloo stops the video and complains about how it shows her turning into a monster (to the confusion of Stumpy and Quack Quack). She then explains: she is Kaeloo, a cute little frog who enjoys playing games with her friends. Then there's Stumpy, an unlucky squirrel who fails miserably at everything he does. And there's Quack Quack, an indestructible duck who is always tormented by Mr. Cat, who wishes to make Kaeloo angry. Mr. Cat shows up and mentions that he likes it when she transforms, and then they continue playing the video, and Mr. Cat shoots Quack Quack at the lights to turn them off. Kaeloo tries to make the video stop, but they ignore her, and the episode starts.
It's a nice sunny day in Smileyland, and Mr. Cat pulls out a lawnchair and decides to enjoy the sun. Unfortunately, his joy is short-lived, since the rest of the main four show up and pull on a nearby rope which changes it to winter. An angered Mr. Cat destroys several trees before reminding the others that it is August 13th and not Christmas, but Kaeloo says they are playing "Winter", not "Christmas". She mentions all the fun things they can do, like skiing, sledding and ice skating. Stumpy starts amusing himself by blowing mucus out of his nostrils and sucking it back in, but Kaeloo makes him stop. Mr. Cat complains about the cold weather, since cats love warmth. Kaeloo tells him not to worry, since she was aware of this.
She pulls another rope which drops a door out of the sky, which leads to a room with a fireplace, a bookshelf, a table and sofas, and says it's for him. He expresses his gratitude to her before settling down in an armchair. Kaeloo suggests a game, and Mr. Cat asks if Bad Kaeloo will be playing. Kaeloo says no, and reveals that they will be playing Guess Who, and she decides to let Stumpy start the game. Stumpy pulls a paper out of the box, which has the word "squirrel" written on it. He points to himself and thinks it will be easy for everybody to guess, but nobody can guess what he's supposed to be (Kaeloo is too stupid to figure out, and Mr. Cat keeps yelling words like "Weirdo" and "Idiot"). Time runs out, and Stumpy loses. He then reveals that the word was "squirrel", and everybody tells him to relax since they never expected him to win anyway.
Kaeloo tells Mr. Cat to start, but realizing that his act involves burning Quack Quack in the fireplace pretending he is a turkey, she angrily tells him to stop. Mr. Cat pulls the rope to turn it back to summer, and Kaeloo pulls it again to make it winter. They repeatedly pull on the rope, and Kaeloo angrily transforms and pulls the rope so hard it comes off. Suddenly, random objects fall from the sky, and everything (including the buddies) starts glitching and fades away.
Fragments of the ground, the objects and the buddies find themselves floating through space. Stumpy thinks that it's cool that the world is ending, and he is happy that there will be no school the next day until he realizes that there is no signal for his phone, so he can't contact Ursula. Kaeloo comes by and explains to him that the world isn't ending, it's just that Smileyland's magic switch has malfunctioned. Mr. Cat decides to see how bazookas work in places such as outer space, and Kaeloo starts to transform, but cannot since her transformations do not work without gravity, to Mr. Cat's horror. Kaeloo tells the others to hold on to a rope, and they all hold on and it pulls them into the "heart" (control room) of Smileyland. They need to climb a ladder that goes in reverse so that they can reach, and they do this and reach the inside. Kaeloo informs that the magic switch is on top of the magic staircase, and Mr. Cat wonders why everything is magic when Stumpy arrives, having finally climbed the ladder, only to fall off again.
Later, after Stumpy comes back, Kaeloo explains to them that they must sit in a chair-like machine to remove all their bad thoughts, and then in 33 seconds (the amount of time before bad thoughts come back) they must climb the staircase and put their hand on the magic switch, which will restore the planet back to normal. Quack Quack is chosen to try, since he is the least likely of the main four to have bad thoughts. He sits on the chair, and his one and only negative thought (personified as a miniature version of himself) pops out of his head. Kaeloo says that it's a very ugly thought, and the thought is revealed through a flashback.
Quack Quack was about to go to bed one night when he felt hungry, but Kaeloo told him that it was time to sleep and took away the yogurt he was holding. After she left the room, he pulled out a secret stash of yogurt he had hidden and started eating, and when Kaeloo came in to check on him he pretended to be asleep.
The flashback ends, and Kaeloo asks a robotic arm for a wooden chest big enough to hold one bad thought. She locks the bad thought in it and it is thrown into a giant toilet which contains a black hole. Quack Quack starts to run up the stairs, and Mr. Cat asks Kaeloo what would happen if a bad thought came back. Kaeloo explains that it would have disastrous consequences, because the thoughts would influence the new Smileyland's programming and change it to be like in their thoughts. Mr. Cat starts daydreaming about a version of Smileyland based on his thoughts where he is being given a massage by numerous Bad Kaeloos. Meanwhile, Quack Quack reaches the switch and puts his hand on it, but at the last moment his bad thought comes back.
The four find themselves in "Yogurtland", a planet where everything is made of yogurt. Kaeloo realizes what must have happened, and Mr. Cat concludes that it's not just important to have a pure heart, but a full stomach as well. He tries firing a bazooka, but instead of a missile with a crayon drawing on it, it launches out yogurt, which Quack Quack eats. Stumpy wonders what happened to Smileyland, and Kaeloo tells him it doesn't exist anymore. Stumpy tries calling Ursula with his phone (now a yogurt container), but she doesn't respond. Kaeloo sadly says that Quack Quack probably wasn't thinking about Ursula when he pressed the switch, so she doesn't exist anymore either. Stumpy, with tears in his eyes, yells at Quack Quack for forgetting about his girlfriend, and Kaeloo also expresses disappointment in him since she had put all her trust in him and he turned Smileyland into Yogurtland, and refuses to ever forgive him. Feeling guilty, the duck grabs every rope there is in Yogurtland and pulls on them simultaneously, resulting in the planet's destruction, and they are left floating in space.
Kaeloo decides to forgive Quack Quack, and then she starts looking for Mr. Cat before seeing him grab a rope and head for the control room. Kaeloo is horrified just thinking about all the horrible thoughts Mr. Cat could be having, and she decides that she and Quack Quack should try to stop him. Quack Quack points out that Stumpy is missing, but Kaeloo ignores him, saying Stumpy will join them, so they set off to stop Mr. Cat from recreating the planet. Meanwhile, Mr. Cat sits in the machine to remove all his bad thoughts, and there turn out to be several of them, such as one who is obsessed with money, one who wants to attack the others with a chainsaw, and one who considers himself doomed. The thoughts start aggressively fighting with each other and using their weapons. Mr. Cat tries to shut one of them in a chest when Kaeloo and Quack Quack show up, and Kaeloo says she no longer has any respect for Mr. Cat.
The thoughts stop fighting with each other and unanimously agree to attack Quack Quack. However, it doesn't work, since he easily fights them all off and locks them in a chest. Meanwhile, Mr. Cat desperately tries to tell Kaeloo that he isn't doing what she thinks he's doing, but she says she will not believe anything he says anymore, and then pretends she can't hear anything he says. Quack Quack captures all the thoughts and locks them in a chest, and then uses the machine to launch them into the black hole. Mr. Cat continues to try to tell Kaeloo what's happening, but she pretends she can't hear him. Suddenly, she realizes that the chest isn't going into the black hole, and she wonders who could be causing this, before realizing: Stumpy.
Mr. Cat then explains that what he's been trying to tell Kaeloo this whole time was that he saw Stumpy holding a rope while laughing like a maniac, and was trying to follow him. Kaeloo is horrified when she thinks of Stumpy's bad thoughts. Mr. Cat informs her that Stumpy is already on top of the staircase (and has been there long enough for his bad thought to grow back), and she tries to go in, but the barrier electrocutes her since her bad thoughts have not been removed. She sits in the chair, which removes her bad thoughts (personified as miniature Bad Kaeloos). Mr. Cat finds them cute, but they keep trying to attack him. Quack Quack points out that since the black hole is blocked, none of them can get rid of their bad thoughts, and she says they can't just wait until Stumpy recreates the world, but Mr. Cat tells her not to worry, since Stumpy can't even choose between a chainsaw and a pair of roller skates, so there's no way he can make enough choices to create a universe before they stop him.
Meanwhile, Stumpy is listening to his negative thoughts, and just as Mr. Cat predicted, he is having trouble choosing how to make his world. Mr. Cat comes up with an idea to get past the barrier: destroying it with his bazooka. He fires the weapon, and before Kaeloo can stop him, the barrier is destroyed. Unfortunately, Stumpy, who "could distinguish that bazooka from a thousand others", realizes that his friends are on their way to stop him, and prepares his bad thoughts to attack. As the negative thoughts rush down the stairs, Mr. Cat prepares to use his bazooka on them, but Kaeloo stops him. She transforms, and the thoughts run away while Mr. Cat gazes dreamily at Bad Kaeloo. Stumpy still can't decide how to recreate the world when Bad Kaeloo charges at him.
Rather than beating him up, she detransforms and questions why Stumpy would want to change Smileyland, and asks if he didn't like it before, pointing out that they all had a lot of fun together back in Smileyland. Stumpy then sings a song explaining how he is tired of being made fun of by everyone around him, and despite how bad he is at everything he can't change, and how he wants a world with Ursula in it. Kaeloo, Quack Quack and Mr. Cat start to feel extremely guilty for all the horrible things they have done to him. Several screens show up with flashbacks from past episodes of all the horrible things they have done to him, and they all look around in horror. Stumpy assures the three that he loves them, but he says wanting happiness isn't a bad thought. He presses his hand against the magic switch.
Realizing what may happen to them, Mr. Cat holds on to Kaeloo's hand and puts an arm around Quack Quack, and Kaeloo places a hand on Stumpy's shoulder. They all look at Stumpy with apologetic smiles, and the screens change to show all the good times they had together as friends. Everything (including Kaeloo, Quack Quack and Mr. Cat) fades away, and Stumpy finishes his song before he also fades away. Suddenly, all four friends find themselves in Smileyland in winter again.
Upon seeing Mr. Cat complaining about the snow, Kaeloo realizes that nothing has changed at all, and is overjoyed. Stumpy gets his phone signal back, and sends a text message to Ursula, and he gets a response. Kaeloo goes around greeting random things such as flowers, grass, and the three secondary characters (who are annoyed to see her), and she realizes that nothing has changed. Kaeloo, Quack Quack and Mr. Cat apologize to Stumpy and promise not to make fun of him again, and he says they can if they want to, just not always. The four of them share a hug, which Mr. Cat ruins by pervertedly squeezing Kaeloo's butt, making her transform and chase after him.
Stumpy sneaks off and maliciously informs the audience that he has everyone else fooled into thinking nothing has changed, and then he opens a secret door behind some bushes. The door leads to the Cube Creative studios, where all the episodes of Kaeloo are made, and he announces to the animators that, from now on, he will be the one writing all the episodes.
- Quack Quack
- Mr. Cat
- When the main four are watching the episode as a video, the Season 1 theme song is used.
- This episode shows clips from various other episodes, and references a few.
- This episode is a 26 minute special.
- This episode has an alternate title, which (translated from French) is "Journey to the Center of Smileyland". The French alternate title is "Voyage au centre du Pays Trop Mignon".
- It is revealed that Kaeloo's transformation cannot take place in zero-gravity conditions.
- In this episode, Mr. Cat claims to hate snow, but in "Let's Play Hallo, Hello, Hola!", he seemed to enjoy playing in the snow with the others.
- It's possible that Mr. Cat developed the hatred of Christmas after the events of "Let's Play Frosted Christmas - Part 2", as at the end of that episode he said that he was glad Christmas only came once a year.
- This is the fourth time it is shown snowing in Smileyland.
- This is the third winter-themed episode.
- Kaeloo explaining the way the magic switch works is a reference to Shaun of the Dead.