On a field on Earth, children ride on a wagon through a field of patients tied up to poles. They arrive home and a young girl, Alit, looks up at the 507 floor sign on the sky. The children go inside, and as night falls one woman, Hazran, comes in with a gun and tells them to hide under the bed as the alarm bell sounds. The parents go out and prepare to fire on the patients advancing toward the house. The adults open fire, killing them, as Alit watches from the bedroom window.
The next day, the adults put the patients back up on their poles Alit wanders off and hears a rumbling noise, and a shuttlecraft blasts up through the ground and flies into the sky. It crashes back to earth and a Mondasian Cyberman emerges, carrying the unconscious Doctor.
The Master and Missy ask the Doctor how many times that he's died. They finally ask him if he has any requests, and the Doctor passes out. He remembers the Master and Missy beating him in the lab, and Nardole running off.
Later on the hospital roof, the Doctor wakes up tied to a wheelchair and finds Missy and the Master dancing. As they talk about their regenerations and flirt, the Doctor finally interrupts and asks where Bill is. They point out that Bill is behind him, and he turns to see the Cyberman Bill. Missy says that Bill is dead and ground up, and squeezed into a Cyberman suit, and the Master explains that the Doctor missed rescuing her by two hours. The Doctor asks what happened to the Master, and he says that they kicked him off. He figures that the Master's TARDIS got stuck, he ended up on the ship, and he took over the city. They eventually rebelled against his cruelty and the Master has been trapped there ever since. Angry, the Master says that now it's Cyberman mass-production
As the Cybermen march down the street, a nearby communication tower glows, and Missy ask the Doctor if he's done something. The Doctor ignores her and says that the Cybermen are just parallel evolution. The Cybermen march on the hospital, and the Doctor says that when Missy hit him, she knocked him onto a keyboard. He changed the Cybermen's algorithm from finding and converting humans, to finding and converting Time Lords.
The Cybermen march up the stairs and Missy seals the roof door. The Master blows one Cyberman up, but there are too many entrances to cover all of them. The Doctor tells his captors that there's only one way to stop that many Cybermen: him. The Master says that he can handle them, and Missy knocks him out. She says that she's secretly been on the Doctor's side all along and unties him. He asks if she's telling the truth, and Missy admits that it's hard to say.
The Doctor runs to the edge of the rooftop and contacts Nardole. Nardole pulls up in a shuttlecraft, and the Doctor and Missy wake up the Master and he boards first.. A Cyberman grabs the Doctor and electrocutes him, and he starts to regenerate. Bill destroys the Cyberman before Missy can, and Missy abandons the unconscious Doctor and boards the shuttle. The Master and Missy go to the cockpit, take over from Nardole, and try to fly off. However, Bill grabs the rope ladder and holds them there. The Doctor wakes up and tells her that he'll fix it.
Missy and the Master emerge from the shuttle and realize that they're on one of the solar farms. Alit asks who they are, and Bill comes out and says that the engine is blown. He tells Alit that they need her help.
Two weeks later, Hazran goes out to the barn with blankets and sets them near a sleeping Bill. Bill wakes up and Hazran says that Bill has to stay out there because she frightens the children. Bill wonders where she is, and Hazran explains that the Doctor put her to sleep. She backs away nervously as Bill gets up and approaches her, and says that the Doctor's injuries are being tended to. Hazran quickly leaves and locks the door behind her.
The next day, Alit enters the barn and says that everyone else is scared to talk to Bill except her. Outside, Nardole is organizing the locals to build barriers and warns that the Cybermen are looking for humans and they're it.
In the barn, Alit brings Bill a mirror. When Bill looks into it, she sees a reflection of her Cyberman self and realizes that she hasn't been changed back after all and is just imagining having her human features. Bill insists that it isn't her, and a frightened Alit starts to run. The Doctor comes in and tells Alit that she was being kind, and offers her a jelly baby. Once the girl leaves, the Doctor tells Bill about the Cybermen. Bill doesn't remember them converting her, and briefly sees herself as a Cyberman. The Doctor explains that Bill's mind has created a barrier to block out what happened, and tells her that what she sees isn't her. He tells her that she can't be angry anymore, and unleashes a blast of energy from her helmet unit. The Doctor says that she can't become angry because she's a Cyberman.
Nardole gets everyone back to work. Bill comes out and everyone stares at her in fear. Bill realizes that people will always be afraid of her, and the Doctor strokes her face and realizes that she's crying. The Master comes up and says that he and Missy have been busy and found it. He assumes Razor's voice and said that it was boring being with her for ten years, but it was worth it to see her as a Cyberman.
As they got to the house, the Doctor explains that the farmers keep the children all together for protection. The patients sometimes make it to the solar farm and try to take the children. The Doctor collapses in momentary pain, and his hand glows with regenerative energy. He stops it through force of will and says that he's fine, and then explains that the Cybermen target the children for conversion because they're smaller and more resource-effective. Bill remembers the Doctor saying that he could fix her, and the Doctor admits that he can't. She tells him that she can feel the programming in her head, and the Cybermen are taking her over peace by peace. Bill says that she doesn't want to live if she can't be her, and the Doctor tells her that where there's tears, there's hope.
Further in the forest, Missy is opening a lift shaft concealed by a hologram. The Master is surprised that she doesn't remember any of what happened in his life, and she tells him that the two of them together is putting the timelines out of sync so he can't retain the memories. The Doctor and Bill arrive, and the Doctor figures that they can use the lift shaft to evacuate the children. He supposes that there are more doors and finds them, and Missy calls a lift. The Doctor warns that it will be coming from the Cybermen's floor, and Bill tells them to stand aside.
The lift arrives and a newer-model Cyberman steps out. All four of them open fire on it, and they finally manage to destroy it. Missy keeps the lift there while the Doctor warns that they gave their position away. He says that they can only go up five floors at a time because the slower times move for them, the faster it moves for the Cybermen. By the time they get to the bridge and the TARDIS, the time differential will mean the Cybermen will have thousands of years to work out how to stop them.
The newer weapon-grade Cybermen fly up through the roof, ignoring the lifts. The Doctor returns to the farm and tells the others that the Cybermen are coming. As Nardole enhancers the farmers' energy rifles, Missy and the Master watch. Missy suggests that they use his TARDIS and go down to the Cybermen's floor to get it. He doesn't answer.
The Doctor takes Bill to the cellar and reveals a service duct entrance. It's rusted shut, and the Doctor asks if Bill can get angry with it.
Nardole blows up a nearby windmill with an enhanced rifle to test its capabilities. He has a farmer shoot a bush with similar effectiveness, and the Doctor says that they're on a spaceship, not a farm. They can fool the Cybermen's brains.
The Master warns that his TARDIS is in the middle of the Cybermen city, and finally admits that it doesn't work. He explains that he landed on the ship and blew the dematerialization circuit trying to escape the black hole. Missy remembers telling herself in the past to carry a spare dematerialization circuit, and takes one out of her pocket. The Master wonders if it's wrong that he's attracted to her, and Missy tells him that it's very wrong.
In the children's dorm room, the Doctor tells Alit that the Cybermen have removed fear from their hearts and minds, and she's going to put it all back.
The Cybermen fly up through the ship's floors.
As the farmers' wait Nardole waits in the kitchen and Hazran asks him who loved him. He tells her that he isn't human, and Hazran says that she's not human. Bill comes in and Hazran shoots at her until Nardole stops her. Hazran apologizes and a shocked Bill goes to the porch and starts to ask the Doctor. The Cybermen blast onto the floor, and Nardole and the others come out. He says that they're ready, and gives Alit an apple to floor. The Doctor then finds Missy and the Master, and they ask what he has planned. He says that there's another solar farm five floors up and hopes to evacuate the farmers there, but admits that it's a temporary measure. The Doctor admits that he can't win, and the Master and Missy leaves. He yells at them to stay and says that he does what he does because it's kind, nothing else. The Doctor tells them that they'll die someday, and asks what they would die for. He looks at Missy and asks them to stand with him. The Master tells him that his face is the one who didn't listen to a word that the Doctor just said., He walks off, and the Doctor tells Missy that he knows she's changed and he knows what's she's capable of. They admit that standing together is all they both ever wanted, but Missy refuses, thanks the Doctor trying, and goes after her younger self.
The Cybermen march on the farm and come to Alit waiting with an apple. She throws an apple into their midst, and Nardole detonates it before leaving with Alit.
The Master and Missy make their way through the forest and see the explosion.
Back at the farm, Nardole tells Hazran that he detonated the fuel lines in the floor. He triggers more weaponry and the Doctor figures that the Cybermen will change their campaign parameters to retreat and plan a bigger assault. Hazran takes the children down to the cellar and the Doctor asks Nardole to lead the evacuation. When Nardole objects, figuring the Doctor will detonate the floor and die with the Cybermen. The Doctor finally admits that's what he's doing, and Nardole says that he'd rather stay than explode. When the Doctor asks him which one of them is stronger, Nardole concedes that he's right and tells Bill to come with her, but she refuses. Disgusted, Nardole bows briefly to them and goes with the farmers.
Missy and the Master get to a lift shaft, and Missy tells the Master to come over to her. He walks over and they hug, and she says that she loved them together, and she'll miss the feeling of hatred burning. The Master tells her that it was nicely done as he realizes that she's stabbed him in the back.
The Doctor tells Bill that they have to buy the others time. They figure that there's nothing else to say, and they split up to cover the house.
Missy tells the Master that he'll be able to get back to his TARDIS and regenerate into her. She admits that the Doctor was right and it's time to stand with him. The Master refuses and shoots her in the back. He tells her that she won't be able to regenerate, and they both laugh. The Master says that it's their perfect ending, shooting each other in the back. He takes the elevator down, still laughing.
Nardole and the farmers emerge get to the lift and see explosions from the farm. The Doctor runs among them, blowing them up with his sonic screwdriver. One shoots him in the back and then shoots him again when he turns around. The Doctor collapses to his knees and starts to regenerate, and tells himself to let it go. He detonates the sonic screwdriver, blowing up everything in the area.
As the Doctor lies dying, he wishes that he could see the stars.
The next day, Nardole waits at the elevator shaft. He assures Alit that it will take a while until the Cybermen regroup and find them again. They go to have breakfast.
The injured Bill walks through the ruined forest and finds the Doctor. She falls to her knees, crying, Heather appears from a nearby puddle, and extracts Bill from the Cyberman body after transforming her into water. The creature leans forward and kisses Bill, and assures Bill that she's not dead. Heather explains that she left Bill her tears, and she could always find her through them. When Bill says that they can't leave the Doctor, Heather says that they're not going to.
Bill and Heather take the Doctor to the TARDIS. Heather offers to make Bill human again if she wants, or Bill can come with her. Before Bill makes up her way, Heather offers to show her the universe. Bill figures that the Doctor isn't dead because people need him too much, and kisses him goodbye... leaving a tear on his face. She then says that she'll show Heather around and the two of them step out the TARDIS doors together.
The Doctor begins to regenerate, and he remembers his companions. He comes back to life and says that he doesn't want to go, and the TARDIS shakes around him. The Doctor refuses to regenerate and dissipates the gathering regenerative energy. The TARDIS materializes and the Doctor tells it that he will never change again because he can't go on being someone else. He walks out of the TARDIS as the cloister bell rings.
On a frozen landscape, the Doctor drives his hands into the snow and insists that he will not change. Another man calls out of the darkness, saying that he won't change. The Doctor calls to him, and the First Doctor steps forward and says that he is the Doctor: the original.
Written by Gadfly on Jul 2, 2017