It’s another case of technology gone horribly wrong, where a smile in a future world keeps you alive.

That’s the story in this week’s Doctor Who, and Bill’s first official trip in the TARDIS.

SPOILERS BELOW

There’s been plenty of Who stories where he visits an Earth colony where something is terribly wrong, and he comes to fix it. It’s pretty weird when emojis are involved as a way to measure a person’s well being. It’s even weirder when someone stops smiling, and a bunch of nano-robots called Vardys decides to devour them and use the remains as fertilizer.

That’s what the Doctor and Bill find in an Earth colony far into the future. They find the emoji-bots, but no people, but by taking a look around they figure out what is happening. It looks like the Vardys killed the preliminary crew who was preparing the spot for incoming colonists, and there were a lot of them.

He thinks the only thing to do is blow up the colony before the Vardys and emoji-bots kill again. However, with the sudden appearance of a young boy, the Doctor learns the colonists are already here because their ship is one of the new buildings.

Eventually, he figures out the Vardys were stunned when one of the preliminary crew died, and the others expressed grief. The Vardys consider grief an “enemy” to the happiness they’re supposed to provide. That’s why they kill anyone who is grieving. The colonists, who have woken up, think they can shoot at the Vardys, The Doctor has a better idea: he resets the Vardys’ memories. Now, they think they are the original inhabitants of the new world, and the human colonists have to “negotiate” their right to move in. It’s a pretty weird ending.

Aside from this story, Pearl Mackie is establishing herself as the Doctor’s new sidekick. She asks a lot of questions about the Doctor, and what he does with his life. She wonders, for example, why his ship is always a police box. She eventually guesses “you don’t call the helpline, you are the helpline.”  She’s also surprised the Doctor has two hearts, and expresses a lot of excitement about being in the TARDIS, but also the spaceship that was part of the new Earth colony housing.

It’s also revealed that the Doctor did something a long time ago, and now he’s “stuck” on Earth, guarding a vault. Nardole (Matt Lucas) reminds him of this, in full office manager mode. What this all means should be pretty interesting.

Anyway, the Doctor assures Bill they’ll be back before the kettle in his office starts boiling. They soon find out they’re wrong, judging by the snow…and an unusual animal. Next week, they’ll find out something sinister is coming from the frozen Thames River.