DOCTOR WHO IN DETAIL

On board the Mondasian Colony Ship (see World Enough and Time) on floor 507, near the bottom of the ship, life seems normal. Except at night. More masked people are arrive. The local population capture the masked people and tie them to crosses to be used as scarecrows.

On the roof of the hospital on floor 1056 the Doctor awakes to see Missy and the Master trying to work out the best way to kill him. All the Doctor is interested in is finding Bill. Missy takes great delight in showing Bill to the Doctor - now that Bill is a Cyberman. The Master then shows the Doctor the city that has been converted into a giant factory turning people into Cybermen.

The Cybermen has been programmed to seek out human life forms. But the Doctor has managed to change the parameters to include Gallifreyan as well. Now that the Master and Missy are no longer safe, and with Cybermen approaching the roof the Master insists he can fight them. Missy disagrees and knocks out the Master and frees the Doctor, telling him that secretly she was on his side all along.

The Doctor calls for Nardole who appears in a shuttle he found in the loading bay. The Master and Missy use a ladder to climb into the shuttle. The Doctor is caught by another Cyberman. The Bill Cyberman kills it, but the Doctor collapses. The Master and Missy are prepared to leave the Doctor, but Bill holds on to the ladder preventing the shuttle from leaving.

With the Doctor and Bill on board Nardole manages to fly the shuttle up several floors to floor 507 where it crashes into a field. The first person they meet there is a young girl - Alit. Alit takes them back to a farm house where other children are being protected. Bill has to stay in a barn to avoid frighten them. The Doctor put Bill to sleep, and she wakes up after two weeks with no memory of what has happened. When Alit hands Bill a mirror Bill can see that she is a Cyberman, even though she does not believe it. Bill asks the Doctor why she sees a Cyberman in the mirror. Bill can't remember being converted. After the incident with the Monks Bill's find has learned to hang on to itself, and so Bill can't see herself as a Cyberman.

The Doctor knows Bill has a temper and asks her not to get angry. When she does a beam fires from above her head and blows a hole in the side of the barn. Leaving the barn she can see people outside preparing for Operation Exodus, when the Cybermen will attack.

Outside the Master tells the Doctor that he and Missy have been busy. He takes the Doctor and Bill to an area of a forest where he and Missy have found hidden lifts that can be used to evacuate the children up to a higher level away from the Cybermen. Missy calls a lift - but the lifts are all on the lower levels. When it arrives it contains an upgraded Cyberman. Will Bill's help it is destroyed, but the Cybermen now know where the humans are, and they have had many years extra to upgrade from Mondasian Cybermen.

Back at the farmhouse the people are worried they won't be able to fight the new Cybermen. Nardole demonstrates that although floor 507 looks like the countryside it is still a spaceship. When certain areas are shot they will explode.

With the Cybermen close the Master and Missy decide to leave (the Master's TARDIS is on floor 1056). When they ask the Doctor what his plan is the Doctor says he is going to evacuate to a higher floor. He's not trying to win, just doing what is right. If he were to leave people would die. If he stays they might live for longer.

When the Cybermen do attack Nardole is able to manipulate systems into exploding. When the Cybermen fall back to re-think their strategy Hazran and Nardole are able to evacuate the children from the farm. Nardole realises that the Doctor plans to destroy the entire level when everyone has been evacuated. Bill decides to stay with the Doctor as Nardole evacuates the children through service ducts to the lifts in the forest.

In the forest, before Nardole and the children arrive, Missy fatally wounds the Master, giving him enough time to reach his TARDIS before he regenerates into Missy. But before he leaves he fatally wounds Missy.

Elsewhere Cybermen are arriving, and the Doctor and Bill are managing to hold some of them off. Surrounded a Mondasian Cyberman fires at the Doctor, triggering his regeneration. As he starts to regenerate the Doctor uses his sonic screwdriver to trigger an explosion to destroy the entire floor. One Cyberman, Bill, survives.

Through the desolation Bill finds the Doctor's body. Alone Bill feels tears, and from a pool of water emerges Heather (see The Pilot). As Bill looks round the sees a Cyberman suit collapse on the wall. She seems to be back to herself, and moments later she, Heather, and the Doctor, are inside the TARDIS and flying in space. Heather and Bill leave the TARDIS to travel through space.

The TARDIS lands and the Doctor is determined to not regenerate. Outside the TARDIS it is snowing, and through a blizzard he sees a figure approaching - the original Doctor.