The Zombie Monks have taken over the planet and have large statues of themselves situated throughout the planet. The Doctor is broadcasting messages to the populace telling them that the Monks have been here centuries, guiding us. The world has turned into an authoritative regime controlled by the Monks. Dissention will result in death. We see a man being taken away and seemingly executed.
Bill Potts starts talking to her imaginary mum when Nardole arrives to tell Bill that he knows where The Doctor is. The Doctor is broadcasting from a ship in the North Sea and so Nardole and Bill Potts hatch a plan to get at the Doctor.
Nardole and Bill Potts make to the ship and manage to get to the Doctor. The Doctor isn't quite as welcoming as he had hoped. The Doctor calls guards who storm the room and aim guns at Bill. Bill takes a pistol from a guard and shoots the Doctor. The Doctor looks like he'll regenerate but doesn't. It turns out the bullets are fake bullets and the regeneration is a fake too.
The Doctor says he must consult Missy who is being held in the Vault under the university. Missy tells the Doctor that he must kill the person who invited the Monks to the planet and that person is Missy. The Doctor won't do it.
Plan B is to break into the Pyramid Cathedral near St. Paul's Cathedral in London and destroy the machine that is sending the messages to the statues and therefore controlling the people.
The Doctor takes a team into the Pyramid and make their way to the central core. One of the team's anti-message machine is broken and turns on the Doctor but is disabled by Nardole.
Inside the control room is what looks like a dead zombie monk connected to the machine sending out messages via the statue. The Doctor attempts to take control of the machine but is unable to. Bill Potts attempts to take control with thoughts of her mother and manages to disable the network. All those who had been under the control of the Monks are freed.