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World Enough and Time was the eleventh episode of series 10 of Doctor Who.

The episode continued the ongoing story arc concerning Missy's rehabilitation, with the Doctor taking Missy on her first adventure and entrusting her with his two companions in an experiment to test how good she has become. It also showed Bill Potts being converted into a Cyberman and displayed what appeared to be the beginning of the Twelfth Doctor's regeneration.

World Enough and Time notably featured the return of John Simm as the Saxon Master, seven years after his last appearance in The End of Time, marking the first time a previous actor of the Master had returned to the television series after being recasted. The episode also showed John Simm's Master acting alongside Michelle Gomez's Missy, marking the first onscreen appearance of more than one incarnation of the Master.

It also marked the return of the Mondasian Cybermen on television for the first time since they were introduced in 1966's The Tenth Planet, and the Cybermen's first significant appearance since series 8's Death in Heaven. The episode depicted a fourth alternative account of the genesis of the Mondasian Cybermen - different origins have been shown in the comics The World Shapers and The Cybermen, and the audio story Spare Parts. This was, however, explained in The Doctor Falls with a reference to "parallel evolution".


The Doctor decides to test how good Missy has become by sending her on a trial run with Bill and Nardole. However, when things go wrong, the Doctor takes over. With Bill trapped in a different time zone, can the Doctor make it to her before it is too late, and who are all those people getting cured?


The Doctor regenerating.

The Doctor stumbles from his TARDIS onto a snow-filled landscape, repeatedly chanting "no" as he falls to his knees. He begins to regenerate.

Sometime prior, while walking through the courtyard at St Luke's University, the Doctor decides to test if Missy can turn good, despite Bill's objections. They discuss it further in St Luke's kitchen, where their short dispute causes the Doctor to become emotional, due to Missy being the closest thing he has to someone else like him, something that amuses Nardole, who takes a selfie with him to chronicle the moment. Later that day, Bill and the Doctor eat together on the University roof, and the Doctor convinces Bill to let Missy try to prove herself. After a brief discussion about the Time Lords and gender stereotypes, Bill confesses that Missy truly scares her. The Doctor tries to promise he can ensure Bill won't die but admits it can't be guaranteed. Regardless, he assures her that he will be there should things get out of hand.

The plan set, the Doctor drops Missy, Bill and Nardole off on a colony spaceship facing a black hole in the hopes of saving it. Missy introduces herself as "Doctor Who" to the cameras, which she claims is the Doctor's real name despite the Doctor denying such. He soon becomes impatient with their progress, walking around the TARDIS eating crisps. Missy finally follows suit by deducing why a distress call was made. She also mocks Nardole and Bill's roles as "comic relief" and "exposition" given their genders. They are soon met by a blue-skinned humanoid named Jorj who demands to know which one of them is a human. Bill confesses that she is human, and the Doctor exits the TARDIS, taking charge as Jorj prepares to shoot Bill as creatures at the bottom of the ship begin to come up in the elevators. Despite the Doctor's pleas, Jorj shoots Bill in the chest, mortally wounding her. Figures with bandaged faces in hospital gowns collect her body, and, using voice synthesisers, claim that they will fix her but shall not return. The Doctor trusts them, leaving a psychic message for Bill to wait for him when she awakes.

The TARDIS lands on a colony ship.

Jorj threatens the Doctor when he attempts to scan the elevators but is threatened by Missy with her umbrella, who states only she is allowed to kill the Doctor and that it will only make the Doctor cross. Once things settle down, the Doctor explains that, due to the lower part of the ship being further away from the black hole, time moves faster on the bottom floors than it does on the top floor that they are in. He notes how lifts slowed down when they neared the top due to the difference in gravitational pull, using a red pen in his sonic screwdriver to illustrate. He also states that the creatures on board the ship are the descendants of the crew who went to the lower part of the ship when it got dragged towards a black hole and needed to be reversed, as decades have passed for them even though it has only been two days for Jorj. Jorj admits his confusion; the Doctor mocks him for his lack of knowledge despite supposedly going to "space school", causing the man to reveal he is only a janitor. The Doctor then knocks out Jorj using Venusian aikido so that he and the others can follow Bill. Nardole, stating it has been ten minutes for them, wonders how long Bill has been living below, to which the Doctor replies he hopes they aren't too late.

Meanwhile, at the base of the ship, Bill awakes in a hospital ward with a cybernetic heart fused into her chest. A feral caretaker looks at her before running off. Coming to her senses, she briefly sees a vision of the Doctor telling her to wait for him only for him to vanish. She observes the room, noticing two clocks on the wall, one for Floor 1056 - which registers 365034 days, 23 minutes, and 26 seconds, or 999.430015 years - and another for Floor 0000, which indicates 2 days, 10 hours, 45 minutes, and 17 seconds.

Bill eventually clambers to her feet and begins to follow the noise of someone chanting "pain", soon finding it be another patient on the ward. She goes to fiddle with its voice synthesiser but has to hide as the feral man and a nurse enter the ward; the nurse mutes the synthesiser. The caretaker, revealed to be called Mr Razor, takes a liking to Bill and brings her to his room. He explains how time passes faster for them compared to those on the top floor, using a tin can to illustrate, and offers Bill tea. He explains how Bill was hurt on the upper levels so had to have her heart replaced with a "shiny" cyber heart and that she has been at the hospital for a few months. He also shows her a live feed of the upstairs, which Bill then spends her time watching despite its extremely slow pace. Months go by, Bill witnessing how the Doctor raised his eyebrow for a week and braced to explain the situation to his associates. While waiting, Bill recovers enough that she is eventually put to work cleaning the hospital by the nurse while plagued by the Doctor's message to keep waiting.

The patients on Floor 1056.

On one particular day, she contemplates leaving the hospital only for it to alarm the other patients on the ward, unnerving her enough to stay. After being there just over a year, she eventually convinces Razor to take her out of the hospital, where he reveals to her that the patients are being converted in preparation for "Operation Exodus" as the humans' finite lifespan cannot survive the journey back up to the top. They witness how the dying residents are guided to the hospital by the partially upgraded. After a while, Bill's cyber heart fails, forcing them back to the hospital.

More years pass, Bill eventually convincing Razor to take her to the elevators so she can be transferred back upstairs. They sneak in, Razor revealing he has a key to the conversion theatre, wearing a mask in skit attempt to disguise himself. However, once inside, it is revealed to have been a scheme to condemn Bill to a full conversion as, according to the surgeon, people usually scream if alerted to the real reason why they are taken into the theatre. The prototype patients in the room restrain her as the surgeon remarks how the headpiece he will fit on her head will inhibit emotion so she won't care about the pain of the process.

Meanwhile, the Doctor, Missy and Nardole make it to the bottom floor, the Doctor having Missy delve into the ship's computer history to find out what has occurred below, annoying Nardole as that tends to be his job. He and the Doctor explore deeper into the hospital, finding a surgery room. The Doctor uses his sonic to activate the light above the bed, Nardole jumping in surprise at there being partially converted patients in the room. Elsewhere, Razor approaches Missy as she researches, the Time Lady threatening to kill him if he comes closer than three feet.

The Doctor discovers he is too late to save Bill.

The others eventually learn of Operation Exodus, while Missy simultaneously learns the ship's origin: Mondas, twin planet of Earth. Razor teases her again, drawing a pistol, agitating Missy enough to confront him directly, but he discards the weapon. Razor states that he is "worried about his future" and is surprised Missy can't remember being on the ship beforehand. He talks to Missy about his love of disguises, wondering if she still likes them, revealing "Mr Razor" was an invention so that Bill did not recognise him as a former prime minister of Britain. He removes his mask, revealing himself as the Saxon Master, in his "Harold Saxon" incarnation, now sporting a beard and grey hair. He greets his future self, smiles and says "give us a kiss".

In the surgery room, the Doctor opens a door, revealing a complete Mondasian Cyberman. Backing away, he confirms he means no harm and asks for Bill's location. To his horror, the Cyberman asserts that it is Bill. Missy and her predecessor enter, the latter surprising the Doctor as they profess they have made "the genesis of the Cybermen". Nardole runs away in fear, as the Doctor looks on in horror; his trial to test Missy's goodness has just been turned upside down in more ways than one. Not only has Missy reverted to her cruel self, the old Master is here too. Bill reaches towards the Doctor and, in the Mondasian Cyberman's stilted, sing-song voice states "I waited. I waited for you..." as she begins to cry beneath the mask.



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General production staff

Script department

Camera and lighting department

Art department

Costume department

Make-up and prosthetics

General post-production staff

Special and visual effects


Not every person who worked on this adventure was credited. The absence of a credit for a position doesn't necessarily mean the job wasn't required. The information above is based solely on observations of the actual end credits of the episodes as broadcast, and does not relay information from IMDB or other sources.






  • The Doctor calls the heart the "most important [human] organ", and notes that humans only have one.
  • The Doctor says he has hidden arms.




  • According to Missy, it is offensive to mistake Time Lords for humans.


Nicknames and aliases[]

  • Missy uses the alias "Doctor Who" and gives Bill and Nardole the nicknames "Thing One" and "the Other One" respectively. Missy claims that the Doctor's real name is "Doctor Who", and that he chose it himself.
  • Missy calls Bill "exposition" and Nardole "comic relief", referring to two types of stock characters typically found in story writing. She calls them their genders.
  • Missy calls Jorj her stallion. Later, she mockingly calls him "Smurf".


  • Missy briefly dabs.
  • According to the Doctor, Time Lords do not have the fixation on gender and gender roles that humans do. Bill remarks that the Doctor's species call themselves "Time Lords", to which the Doctor responds "yeah shut up".
  • Nardole takes a selfie with the Doctor.
  • The creation of the Cybermen on Floor 1056 is codenamed "Operation Exodus".
  • The episode's title is taken from the first line of a poem by Andrew Marvell, called 'To His Coy Mistress'. The poem advocates for living life to the fullest, because death is always approaching.

Foods and beverages[]


  • Shortly after fully waking on Floor 1056, Bill hears opera music playing from the Conversion Theatre whilst work occurs in there.

Story notes[]


Brian Minchin Talks World Enough And Time - The Aftershow - Doctor Who The Fan Show

This episode's Aftershow on Doctor Who: The Fan Show.

  • World Enough and Time marks the first appearance of the original design of the Mondasian Cybermen in a televised story since the Cybermen's debut story, The Tenth Planet in 1966.
  • This episode also marks the return of John Simm's Master, who last appeared in The End of Time in 2010. It also marks the first time that more than one incarnation of the Master has appeared on-screen together.
  • The Master's line comparing Operation Exodus to being more like a "Genesis of the Cybermen" is a reference to the 1975 Doctor Who story Genesis of the Daleks, which showed the Fourth Doctor being sent to the creation of the Daleks. Following the success of Genesis of the Daleks, a story entitled Genesis of the Cybermen was planned, but never produced (although this is just one of many later stories to take up the concept, a full list of which can be found at Genesis of the Cybermen). It is also a play on Operation Exodus and the biblical books of Exodus and Genesis. Perhaps coincidentally, Doctor Who Magazine had previously published a trilogy of stories entitled Exodus/Revelation!/Genesis!, which also featured the Cybermen. Also, Genesis and Revelation (but not Exodus) have been used as titles in the '...of the Daleks' formula.
  • For the first time in the show's history (but far from without precedent across the franchise), the Doctor actually self-identifies using the name "Doctor Who". He has previously been referred to as such in the TV series (examples from across the franchise being far too numerous to list): in The War Machines, WOTAN says "Doctor Who is required" due to a script mistake; in The Highlanders, the Second Doctor introduces himself as "Doktor von Wer" (German for "Doctor [of] Who"); in The Underwater Menace, the Second Doctor signs a note with "Dr. W."; in The Dæmons, the Third Doctor is introduced as "the great wizard Qui Quae Quod" (Latin variations of "Who"); from Doctor Who and the Silurians to The Five Doctors, the Doctor's car Bessie's plate read WHO 1, and in Battlefield it read WHO 7, and in Rose, a website called whoisdoctorwho.co.uk asks "Who is Doctor Who?". Although Missy claims that "Doctor Who" is the Doctor's real name, she also explicitly says she calls herself Doctor Who to head off the usual response heard when the Doctor introduces himself and people reply, "Doctor who?". She also states that he chose the name himself, suggesting she means "real name" in the sense of self-designation.
  • "Operation Exodus" was a continual concern for the inhabitants of Moonbase Alpha in the 1970s TV series Space: 1999. There, it was an evacuation plan for an orderly transfer of the Moon's inhabitants to another location - originally back to Earth but eventually adapted to any habitable body.
  • When the Master unmasks himself, an alarm bell in the background sounds in time with a drumbeat. The drumbeat is also heard when he enters the operating theatre alongside Missy. The Master has had an association with drums before in TV: Utopia, The Sound of Drums, Last of the Time Lords and The End of Time.


  • 3.37 million (UK Overnight figures)
  • 5.01 million (UK final)[1]

Filming locations[]

Production errors[]

If you'd like to talk about narrative problems with this story — like plot holes and things that seem to contradict other stories — please go to this episode's discontinuity discussion.

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Home video releases[]

DVD releases[]

This episode was released as part of the Series 10 DVD box set on 13 November 2017.

Blu-ray releases[]

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Digital releases[]

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External links[]