Written by Frank Cottrell-Boyce, directed by Lawrence Gough. Guest star: Ralph Little
“Between here and my office, before the kettle boils, is everything that ever happened, or ever will. Make your choice.”
In the far future, at the edge of the galaxy, there is a gleaming, perfect city. This brand-new human settlement is said to hold the secret of human happiness – but the only smiles the Doctor and Bill can find are on a pile of grinning skulls. Something is alive in the walls, and the Emojibots are watching from the shadows, as the Doctor and Bill try to unravel a terrifying mystery…
Opening where The Pilot left off, The Doctor and Bill are in the TARDIS. She asks him a number of questions about the machine, including how he steers it when the seats are so far away from the console and how much it costs, to which he replies that he stole it, which she is very intrigued to hear. She seems to enjoy this new side of her tutor that she has never seen before. There is a knock at the door and The Doctor answers it to see Nardole. Nardole scolds The Doctor for having Bill in the TARDIS and suspiciously asks him why the TARDIS is not in his office and reminds him that his is not allowed to go off world because of the vault. The Doctor assures him that they will be heading back to his office and asks him to put the kettle on. When Nardole leaves, he tells Bill that they can go wherever they want and be “back in time for tea”, as it were. He gives her the choice of past or future. She chooses future, and he pulls the lever.
On a distant planet, in the distant future, some human colonists are living in a new colony. While one woman arrives back at the colony after pollinating wheat, another tells her, over the intercom, that there is a problem with the Vardis, microscopic robots that assist in the operation of the colony. When the first woman arrives, the second woman begins to tell her about a multitude of people who are now dead, all the while smiling and begging her to smile as well. When she doesn’t, the small robots that show emojis on their faces begin to show sad faces. When it gets to two tears, the emojibot grabs her while the Vardis destroy everything but her bones. When the first woman runs away, they do the same to her.
The Doctor and Bill arrive at the colony. While exploring, The Doctor explains the Vardis and their function, as well as the fact that the emojibots are the interface used to communicate with the Vardis. As the emojibots guide them throughout the facility, Bill is in awe of the way it’s been set up while The Doctor is skeptical of the situation. He wonders where all of the people are. Soon, he deduces that the robots have been sent up ahead to get the colony ready for the humans. When Bill and The Doctor are guided into a garden, and the emojibot walks away, The Doctor reveals that there would have been a crew here as well, to help get the colony ready. He opens the compost bin and the skeletons of the preparation crew fall from the bin.
They head toward the door of the greenhouse and run into an emojibot on the way. They tell it that everything is fine and they make their way past. As they run, they are cornered by other emojibots. The Doctor figures out that as long as they keep smiling, they can trick the emojibots and will be able to escape. Once past the group of emojibots, they make their way to the TARDIS. The Doctor tells Bill to stay there while he gives into his childlike urge to blow the place up.
Bill waits in the TARDIS, briefly, before running to meet up with The Doctor. He explains that the entire building is made up of the Vardis and that they need to find the original ship that the building would have been built out from. They find the ship and The Doctor leaves Bill to guide him through the ship, using the map on the wall. He heads into the core of the ship to destroy it. Eventually, Bill realizes that The Doctor was just trying to keep her from harm and she follows him. On the way, she finds herself in a room with a woman lying dead on a table. She begins watching a series of photos documenting the history of the human race to find out what happened that forced the colonists to leave the planet. As she watches, a young boy enters the room and begins asking where the other people are. She attempts to tell The Doctor about him, but he is busy fighting off an emojibot in the engine room. When he fights him off, he begins to leave and sees the boy.
The Doctor realizes that he was very wrong about the rest of the colonists, and that they were in cryosleep on the ship the whole time. He stops the ship from exploding and Bill shows him the dead woman. He explains that the Vardis were created with the directive to keep the humans happy. They had never encountered grief, so when the woman died, the Vartis decided that in order to remove the unhappiness and keep the colonists happy, they needed to eliminate the grief-stricken people. He and Bill decide that the best thing they can do is explain all of this to the waking colonists and convince them to refrain from feeling grief over the lost colonists. When hearing the explanation, they instead decide to destroy the robots. As this is happening, however, the boy leaves the ship in search of his mother, the first woman to be seen destroyed by the Vartis.
When the colonists collect their weapons and head toward the rest of the building in search of the emojibots, they find two of them with the boy. They raise their weapons as he asks where his mother is. Bill tries to get him to smile. He begins to become sad. The emojibots grab the boy’s wrists for the Vardis to destroy him. The colonists shoot and destroy one, allowing the boy to escape. The Vardis swarm and begin to destroy the colonists as they shoot into the swarm. In the confusion, The Doctor rips apart the broken emojibot and uses his screwdriver to “reset” the parameters of the Vardis programming. They have achieved sentience, and he removed any memory of the colonists and any protocols that dictate they make the humans happy. He convinces the colonists that they have no memory of killing their loved ones and that, given their strength, have no choice but to live in peace with them. He explains that the Vardis are essentially the indigenous life form on the planet now and helps with peace negotiations.
As they leave, Bill asks The Doctor if this is the kind of thing he usually does. He explains that he just passes through and helps out when he gets mixed up in things. They take off and head back to Earth. Assuming they have arrived right when they left, they exit the TARDIS to find that they have actually landed in Regency London.