Campaign Mode is composed of four chapters that tells the canon events of the Slendytubbies saga, featuring most of the characters from the previous opuses.
You play as the main protagonist - The Guardian.
Chapter 0 - It Was Good
In a distant land lies underground machines, created by the unknown; capable of creating life forms. These machines have been creating creatures known as teletubbies for hundreds of years. The machines worked in a secret underground lair. One of their creations known as the "teletubby guardian", who had white fur; was designed to monitor a test group of four teletubbies in secret. They were known as "Tinky winky, Dipsy, Laa Laa and Po". The four teletubbies lived together in a dome-like home within a boxed landscape known as the "main land". The group were like hampsters in a cage, not knowing that they were being monitored within a fixed area. They also lived with a artificial intelligent machine known as "Noo Noo". The teletubby guardian monitored the groups behavior and documented it into a database, ensured the groups health and also had to ensure that the group did not leave the area. Over the years the guardian grew a strong bond with the group, enjoying watching over them, despite the group not knowing of the guardians existence. One day, things went horribly wrong.
The player controls Po. The beginning starts with a dialogue between her and Noo Noo, who left The House to look for her. Later, the player will interact with her friends and will make Tubby Custard for each of them.
During Night, Tinky Winky behave strangely and destroy the Custard Machine before leaving The House. Po, who wasn't able to sleep, witnessed the scene and have two choices.
- Waking the others: She wakes Laa-Laa and Dipsy and tells to them what happened. Laa-Laa will help Po at searching Tinky Winky, while Dipsy will stay in The House, in case he come back.
- Searching Tinky Winky alone: She don't wakes the others and go outside alone.
She finally find Tinky Winky at the beach (with Laa-Laa's corpse lying on the ground, if Po decided to wake her) and the latter turn back, revealing his changed face while screaming loudly. Po, scared, run towards The House to then discover that Dipsy has been killed as well (and Laa-Laa having disappeared, if she decided to not wake her). She then tries to escape Tinky Winky in the nature but gets caught at the feet of a big tree.
Chapter 1 - A New Day
It has begun, Tinky Winky has killed Po and the rest of his friends. You believe that the custards are responsible for his attacks. You use your computer in an attempt to contact other tubbies at the satellite station, but with no success. Without any delay you prepare a plan to find all of the infected custards before travelling to the satellite station for help. It's up to you to find out the truth.
After have witnessed the incident, The Guardian tries to contact the Satellite Station, without success, and have no choice but to reach it on foot. Since it's night, he decides to grab his night-vision camera by unlocking the storage room door but a power outage happens just after in his lair and three New Borns came from nowhere. His must leave the lair without being spotted by any of these.
Once outside, The Guardian collect the few custards that are scattered around the land, while being sure to avoid Tinky Winky, who is still roaming around. He will eventually find Po, hanged on the tree that is on her last known location. After have collected 4 custards, The Guardian find Tinky Winky standing in front of the last custard.
The sky starts to be stormy, the rain falls and the custard move towards Tinky Winky, having contact with him. Soon later, Tinky Winky become a huge and muscular creature and directly chases The Guardian, who have two choices:
Chapter 2 - The Journey
At the last custard location you encountered Tinky Winky. He transformed into a monster right before your eyes and tried to kill you. You were able to escape to the cave. From there you must travel through maze-like corridors to get to the outskirts. Once you're at the outskirts, you'll find the satellite station.
The Guardian entered the cave to escape Tinky Winky who is not able to enter it. He is now in a labyrinthine cave and must find the exit but it is not easy since the place have a lot of dead-ends and pits. On his way, he will eventually find notes on the ground, written by an experimented teletubbie. However, The Guardian is not alone in this cave, and will notice it when a big brown teletubbie will start to chase him.
After have escaped him, the brown teletubbie is now looking for him and The Guardian must try to find the way without being spotted. Near the end, The Guardian meet one more time the brown teletubbie but success to escape him for good, finding the exit at the same time.
At the last custard location you encountered Tinky Winky. He transformed into a monster right before your eyes and tried to kill you. You were able to escape to the mountains. The mountains strech out for miles, they are cold and almost inhabitable. You must travel through them and get to the outskirts. You'll be able to find the satellite station from there.
The Guardian entered the mountains to escape Tinky Winky who probably gave up. He is now walking in a cold and snowy landscape and hear a voice from far. By approaching the voices, a big silhouette charges him and knock him out. He is taken away by this creature that won't answer him, and wake up surrounded by blood, meat and organs.
Not far from this area, The Guardian find a camp fire and a mechanical humanoid cutting woods. By talking with the security droid, The Guardian learn that it is cutting woods for its master and must cook him before dawn. Not wanting to become food, The Guardian leave but is soon later chased by "The Master", yet escape it and find the gate leading to the outskirts.
After have took the cave or the mountains, The Guardian finally reach the Teletubby Outskirts and will find Laa-Laa:
- If Po woke up her during Chapter 0: Laa-Laa got killed by Tinky Winky the last night, and became a monster as well but became blind, since Tinky Winky scratched out her eyes. The Guardian will have to collect the eight custards that are scattered around while avoiding her. Once finished, Laa-Laa blocks the path that lead to the exit and The Guardian must find a way to get rid of her. He finds it by lauching a rock at a pillar, attracting Laa-Laa and making her attacking the pillar, which makes the pillars falling on her. From this, The Guardian have the choice to kill or spare her.
- If Po didn't woke her: Laa-Laa is found normal and alive. The Guardian, disturbed, approaches her but the latter is scared of him as he is an unknwon person in her knowledge. A discussion occurs between the two characters and Laa-Laa, despite her suffering, tries to follow The Guardian. Once at the exit, Laa-Laa begins to weaken and The Guardian will have the choice to put her out of misery or spare her.
Chapter 3 - Run Away
You've traveled a long way, You escaped those creatures at the Secret Lair. You ran away from Tinky Winky's new phase at the main land. You made your way through the Outskirts and encountered Laa Laa. But after all that's happened so far, you're still alive. At last, you arrive at the Satellite Station.
The Guardian finally reaches the Satellite Station and enters it, just to find an empty place with the corpses of blue teletubbies. He then learn that a green headless monster entered the building and killed everyone, by talking with the sole survivor of the attack: Ron. The Guardian must find a way to access the Secret Center to call the Military but need a key-card to open the door and so, have to go further in the building, while Ron is killed by the monster he mentionned. Before finding the key-card, The Guardian have hallucinations and start to see Tinky Winky, Laa-Laa and Po.
He only hallucinate Dipsy before finding what he became: an headless being holding a chainsaw, responsible of the satellite station massacre. The Guardian returns at the entrance to attract him towards the security laser that will kill him after contact. The Guardian then take his chainsaw in case he needs it and continue his way until the Secret Center.
By entering it, The Guardian gets disturbed by Noo Noo's presence. The latter reveal that he was the one behind the infection, having infected the custards to make the teletubbies "better". No matter the player's choices, Noo Noo underestimate The Guardian by considering him being "too weak" and send The Announcer to kill him. A fight then occurs between The Guardian and the giant fighting robot, and the white teletubbie wins the battle and calls the Military.
The Guardian then catches up Noo Noo at the entrance of the building. The latter reveal that he also put his virus into the Teletubby Creation Machine and created an army of New Borns. The player has 2 choices: accept to help Noo Noo in his evil plan, or refuse it.
If The Guardian refuse, Noo Noo will send Po to kill him. A fight then occurs between the two teletubbies.
- If The Guardian fails: Po deal a final blow at The Guardian and escape with Noo Noo. Latter, the Military arrive and discover the white teletubbie's corpse. Soon later, the New Borns arrives and presumably kill all of the soldiers. Bad Ending
- If The Guardian wins: Po is defeated, Noo Noo has no more issues, it was his last chance. The Guardian, merciless towards the vacuum cleaner and what he've done, destroys him with the chainsaw. The Military then arrives and a short discuss occurs between The Guardian and the Sergeant just before the New Borns appears. Good Ending
If The Guardian accept, Noo Noo will invite him to go to the Custard Facility, where his entire plan started and will soon be completed. The Guardian meet Po at the same time. Noo Noo says to him that he just have to eat a custard to become an infected at his turn.
- If The Guardian accept: Po give him the custard, which transform into what Noo Noo will call "the greatest reborn" and possibly the most dangerous and powerful of the infected teletubbies. Evil Ending
- If The Guardian refuse: Po cuts his legs and pushes him in the Custard Main Supply, which will turn him into an infected. However, he lost his legs in the fall. Regretful Ending
- If you pick Doge Language, the game will be in Dirty English.
- Laa Laa will go through the cave to escape Tinky Winky, she mentions that she had a rough time escaping the brown teletubbie if The Guardian talks to her on Outskirts.
- Getting all endings, The Player will unlock the antennas of the four main teletubbies in Multiplayer Mode.