The alien Monks rule the Earth. In fact, they appear to have ruled Earth for millions of years, as they were there guiding our ancestors when they crawled out of the ooze. Bill (Pearl Mackie) and a few others know it has only been six months. Such people are arrested for memory crimes. The Doctor (Peter Capaldi) appears on TV extolling the Monks’ virtues as loving guides to the human race.

Bill imagines that she talks to her long-dead mother. Nardole (Matt Lucas), who has survived the world-ending bacteria because he is partly android, finds Bill and together they track down the prison hulk where the Doctor is kept. With a team of commandoes, they make their way inside and the Doctor tells Bill he is co-operating with the Monks because they guide Humanity so well. Bill is enraged and shoots the Doctor, and he begins to regenerate, but that was only a test to see if Bill was under the control of the Monks (and to make a spectacular coming attraction).

At the university where the Doctor and Bill work, they enter the vault to talk to the imprisoned Time Lord Missy (Michelle Gomez). She has met the Monks before and knows they are broadcasting their false history through the statues of them all over the world. The best way to break their control is to kill the person who gave the consent for them to take over the planet—that’s how Missy defeated them before—a simple, easy murder. The trouble is that this is Bill herself.

Hoping for another solution, the Doctor, Nardole, and the commandoes infiltrate the Monks’ London pyramid, so the Doctor can hijack their psychic broadcast. The Doctor attempts to link his mind to the controlling Monk but is defeated. Bill intends to sacrifice herself, despite the Doctor’s protests. But the Monks’ broadcast is replaced with images of Bill’s loving mother that flood the world. Humanity recovers from the Monks’ lies and rebels. The Monks abandon Earth, and after a while humanity forgets they ever existed. Missy is sorry for the lives she has snuffed out in her various regenerations.

Missy plays Erik Satie and Scott Joplin on her piano. The episode’s ratings were not good because it aired opposite the Britain’s Got Talent final, though the Doctor, Missy, and Bill were praised by critics. There are several references to 1984. Missy says Nardole looks like an egg, a reference to Matt Lucas playing Tweedledum and Tweedledee in Alice in Wonderland. He uses a Tarovian neck-pinch, which is very similar to the Vulcan variety. Some reviewers were disappointed that the Monks, who seemed so powerful in the two previous episodes of the Monks Trilogy, were so easily defeated.