Colony ship (World Enough and Time)

A Mondasian colony ship travelled from Mondas to pick up some colonists. When the ship almost traversed into a black hole, the crew experienced the effects of time dilation, causing time on the higher levels of the ship to slow down in comparison to the lower floors, to the point that a thousand years passed on Floor 1056, the lowest floor, in the space of less than two and a half days on the flight deck.

When a team of engineers found themselves trapped on the bottom floor, they were forced to spent the rest of their lives down there; a thousand years after settling on Floor 1056, a huge city had formed and eventually degenerated significantly after centuries of occupation by the ship's engines. To survive, the residents evolved into Mondasian Cybermen, (TV: World Enough and Time) and after – who had crashed his TARDIS on Floor 1056 more than ten years prior –  lost control of them, the Cybermen spent centuries evolving themselves into more advanced forms, determined to convert the entire ship and complete the final stage of their original mission: Operation Exodus. (TV: The Doctor Falls)

Layout
The ship was approximately 400 miles long and around 100 miles wide.

Decks
The ship contained over a thousand decks, with various different purposes and landscapes. These included:
 * 0000 - The ship's flight deck. (TV: World Enough and Time)
 * 0502 - A deck containing a solar farm. (TV: The Doctor Falls)
 * 0507 - A deck containing the largest of the ship's solar farms. (TV: World Enough and Time) The locals here were saved from the Cybermen by the Twelfth Doctor, Bill and Nardole, although the floor was reduced to an incinerated wasteland as a result. (TV: The Doctor Falls)
 * 0508 - An agricultural deck, designed to automatically produce food for the floor's population, as well as those of the nearby floors, such as Floor 0507. Sometime after being abandoned,, and Alit prevented a Cybermat attack from some CyberNeomorphs. (PROSE: Alit in Underland)
 * 0900 - A city deck. The Cybermen flew through this floor on their way to Floor 0507. (TV: The Doctor Falls)
 * 1056 - An urban deck, containing various apartment blocks and a hospital. (TV: World Enough and Time) Eventually turned into a Cyber-factory. (TV: The Doctor Falls)
 * Other floors mentioned on the lift scanner are: 1052, 1051, 1050, 1049, 1048, 1047, 1046, 1045, 1044, 1043, 1042, 1041, 1040, 1039, 1038, 1037, 1036, 1035, 1034, 1033, 1032, 1031, 1030, 1029, 1028, 1027, 1026, 1025, 1024, 1023, 1022, 1021, 1020, 1019, 1018, 1017, 1016, 1015, 0951, 0950, 0949, 0948, 0947, 0946, 0945, 0944, 0943, 0942, 0941, 0940, 0939, 0938, 0937, 0936, 0935, 0934, 0933, 0932, 0931, 0930, 0929, 0928, 0927, 0926, 0925, 0924, 0923, 0922, 0921, 0920, 0919, 0918, 0917, 0916, 0915, 0914, 0913, 0912, 0911, 0910, 0909, 0908, 0907, 0906, 0905, 0904, 0903, 0902, 0901, 0899, 0898, 0897, 0896, 0895, 0894, 0893, 0892, 0891, 0890, 0889, 0888, 0887, 0886, 0885, 0884, 0737, 0736, 0735, 0734, 0733, 0732, 0731, 0730, 0729, 0728, 0727, 0726, 0725, 0724, 0723, 0722, 0721, 0720, 0719, 0718, 0717, 0716, 0715, 0714, 0713, 0712, 1711, 0710, 0709, 0708, 0707, 0706, 0705, 0704, 0703, 0702, 0701, 0700, 0699, 0698, 0697, 0696, 0695, 0694, 0693, 0692, 0691, 0690, 0689, 0688, 0687, 0686, 0685, 0684, 0683, 0682, 0681, 0680, 0679, 0668, 0667, 0666, 0665, 0664, 0663, 0662, 0661, 0660, 0659, 0658, 0657, 0656, 0655, 0654, 0653, 0652, 0651, 0650, 0649, 0648, 0647, 0646, 0645, 0644, 0643, 0493, 0492, 0491, 0490, 0489, 0488, 0487, 0486, 0485, 0484, 0483, 0482, 0481, 0480, 0479, 0478, 0477, 0476, 0475, 0474, 0473, 0472, 0031, 0030, 0029, 0028, 0027, 0010, 0009, 0008 and 0007. (TV: World Enough and Time)
 * Other floors mentioned on the lift level indicator at Floor 0000 are: 0995, 0994, 0993, 0992, 0991, 0990, 0989, 0988, 0987, 0986, 0985, 0984, 0983, 0982, 0981, 0980, 0979, 0978, 0977, 0976, 0975, 0974, 0973, 0972, 0971, 0970, 0969, 0968, 0967, 0966, 0965, 0964, 0963, 0962, 0961, 0960, 0959, 0958, 0957, 0956, 0955, 0954, 0953, 0952, 0363, 0362, 0361, 0360, 0359, 0358, 0357, 0356, 0355, 0354, 0353, 0352, 0351, 0350, 0349, 0348, 0347, 0048, 0047, 0046, 0045, 0044, 0043, 0027, 0026, 0025, 0024, 0006, 0002 and 0001. (TV: World Enough and Time)
 * Further floors mentioned on the lift level indicator at floor 0507 are: 0797, 0796, 0795, 0794, 0793, 0793, 0792, 0791, 0790, 0789, 0788, 0787, 0786, 0785, 0784, 0783, 0782, 0781, 0780, 0779, 0778, 0777, 0776, 0775, 0774, 0773, 0772, 0771, 0770, 0769, 0768, 0767, 0766, 0765, 0764, 0763, 0762, 0761, 0760, 0759, 0758, 0757, 0756, 0755, 0754, 0753, 0752, 0751, 0750, 0749, 0748, 0747, 0746, 0745, 0744, 0743, 0742, 0741, 0740, 0739, 0738, and 0509. (TV: The Doctor Falls)
 * Although she did not specify any floor numbers, Alit stated that there were laboratory levels. (PROSE: Alit in Underland)

Each level from the bottom and up would move a little slower than the one below it, due to the time differential, from proximity to the black hole. (TV: World Enough and Time, The Doctor Falls)

Crew
At take off, there were fifty crew members aboard the ship. They included at least twenty engineers, the chief engineer Franq, the Captain (PROSE: Jorj), and Jorj, the janitor, (TV: World Enough and Time) and the man responsible for checking for stowaways prior to the ship's launch from Mondas. (PROSE: Jorj) Following the effects of the time dilation from the black hole, the bottom floor became filled with generations of lifeforms, each descended from the ship's crew, in a huge city. The hospital on this floor became the genesis point for a race of Cybermen. (TV: World Enough and Time) A colony of farmers and children lived on Floor 0507, although following the Cybermen's attack, they were evacuated by Nardole and Hazran to Floor 0502. (TV: The Doctor Falls) A team of farmers were also based on Floor 0508, although their whereabouts following the rise of the Cybermen on Floor 1056 was unknown. (PROSE: Alit in Underland)

Technology
The ship was fitted with super-fast inertia lifts and was propelled by rear thrusters. Aboard the lowest decks, evolution of technology was advanced. In order to adapt to expiring environments, an artificial evolution was devised. The Mondasian inhabitants were gradually upgraded into Cybermen. (TV: World Enough and Time)

The black hole
At an unknown time after the human Mondasians had evolved on Mondas, the colony ship was launched from Mondas to pick up some colonists, with a skeleton crew of fifty, including the Captain, chief engineer Franq and Jorj, the janitor and only non-human. On day 43 of its voyage, it was drawn into the gravity well of a black hole. After the Captain berated Jorj for not alerting him of the black hole sooner, a team of twenty engineers, including Franq, were sent from Floor 0000, the flight deck, to Floor 1056, the lowest level, to reverse the rear thrusters and escape the black hole. However, time dilation caused by the black hole's gravity resulted in time passing much more slowly on the higher floors of the ship in comparison to the lower floors, as the higher floors were closer to the black hole. (TV: World Enough and Time, PROSE: Jorj)

The deterioration of Floor 1056
As a result, the team at the bottom of the ship found that, after reversing the rear thrusters, they were unable to return to Floor 0000. Forced to spend the rest of their lives on Floor 1056, they established a huge civilisation that their descendants inherited over several centuries, but over time, the city deteriorated significantly as the bottom of the ship aged dramatically, whereas the higher floors, in particular Floor 0000, aged far more slowly. (TV: World Enough and Time)

At some point,, after being cured of his "little condition" and banished from Gallifrey, (TV: The End of Time) arrived on Floor 1056; he attempted to escape the black hole but flew his TARDIS too fast, burning out the dematerialisation circuit and stranding him on the colony ship. The Master then "killed a lot of people, took over the city [and] lived like a king" before the people of Floor 1056 got tired of his cruelty and overthrew him. The Master was forced into hiding as "Mr. Razor", (TV: The Doctor Falls) the caretaker of the city's hospital.

Operation Exodus
By this time, conditions on Floor 1056 had rendered the floor inhospitable to human life, to the point that the hospital began Operation Exodus, an operation with the intent of transforming the people of the city into cyborgs to dramatically extend their life spans, so that they could not only survive on Floor 1056, but also survive the journey to Floor 0000 to take command of the ship. (TV: World Enough and Time) However, following the manipulation of Razor, the cyborgs that were produced from Operation Exodus were a race of Cybermen (TV: The Doctor Falls) that the Master intended to use to conquer the galaxy. (PROSE: Alit in Underland) The "patients", an early form of Mondasian Cybermen, were converted from humans by the hospital's surgeon in the conversion theatre, although they were insufficient as a final solution to Operation Exodus as they were in constant pain from the conversion process. Although a temporary solution was found in the development of voice synthesisers that allowed the patients to be muted, a permanent remedy to the problem was needed, and thus both the patients and the primitive Cyber-Technology continued to evolve over the years.

Whilst the patients were used to escort people from the city to be converted in the hospital, they were also sent to the higher decks to capture any other humans for conversion. (TV: World Enough and Time) One team of patients were sent to Floor 0507, but were attacked by the farmers living on the floor, who shot them down at night and chained them to crucifixes in the fields during the day. However, at night, the patients sometimes broke free and resumed their original mission, forcing the farmers to constantly fight them off. (TV: The Doctor Falls)

Bill's new life
On Floor 0000, the day after Franq and the original twenty engineers were sent to Floor 1056, Jorj detected hundreds of life readings at the bottom of the ship. The Captain sent another team to Floor 1056 to deal with the "stowaways”, but when the lifts returned, a patrol of patients arrived, who captured the remaining humans and took them back to Floor 1056, leaving Jorj behind due to him being non-human.

By the next day, (PROSE: Jorj) Jorj had broadcast a distress signal; in response, the Doctor's TARDIS arrived, and, Bill Potts and Nardole emerged. Initially monitoring the trio from inside the TARDIS, the Twelfth Doctor quickly emerged when Jorj arrived and threatened to shoot them, after Bill's human life-signs were detected by the hospital on Floor 1056, who, in response, sent a team of patients in the lifts to capture her. When the lifts arrived, Jorj shot Bill despite the Doctor's efforts to stop him, and the patients took her back to Floor 1056. The Doctor left a message in Bill's subconscious to "wait for [him]", and after explaining the effects of the time dilation on the ship to Jorj, proceeded to knock the janitor out before he travelled with Missy and Nardole in a lift to Floor 1056, stating that he'd never be able to fly the TARDIS properly in such close proximity to the black hole, thereby preventing him from time-travelling back to rescue Bill as soon as she arrived at the bottom floor. (TV: World Enough and Time) During their descent, a portal opened inside the group's lift, and a hand emerged asking for them to "grab on", before quickly disappearing. (COMIC: The Road To...)

In the time that the Doctor, Nardole and Missy were on Floor 0000 with Jorj, Bill woke up in the hospital on Floor 1056 after months of sleeping, having been fitted with a chest unit by the surgeon to replace her destroyed organic heart. She discovered a ward full of patients before being discovered by Razor, who took her to his office and made her some tea while explaining the time dilation affecting the colony ship. As her chest unit could only function within the hospital, this meant Bill was unable to return to the Doctor on Floor 0000, instead having to wait for him, as he had instructed her to, over the course of ten years whilst the Doctor, Nardole and Missy spent, from their perspectives, only ten minutes on Floor 0000. Bill predominantly spent these ten years working as a cleaner in the hospital, whilst also watching the Doctor very slowly progress through his conversation with Jorj on the flight deck. During her new life, Razor explained to Bill the purpose of Operation Exodus, (TV: World Enough and Time) purposefully leaving out his intentions to use the resultant Cyber-race as his personal army, (TV: The Doctor Falls, PROSE: Alit in Underland) and, after Bill saw the Doctor, Nardole and Missy entering one of the lifts, was eventually persuaded by Bill to grant her access to the conversion theatre one night. However, it was a trap by Razor, the surgeon and the nurse. Against Bill's will, the surgeon converted her into the first full Mondasian Cyberman, before leaving her in a small storage room (TV: World Enough and Time) and commencing the total Cyber-conversion of Floor 1056. (TV: The Doctor Falls)

Rise of the Mondasian Cybermen
Two hours later, the Doctor, Nardole and Missy's lift reached Floor 1056, emerging in a small area behind the city hospital's conversion theatre. Leaving Missy to investigate a nearby computer terminal to identify the ship's planet of origin, the Doctor and Nardole entered the conversion theatre and found information on Operation Exodus, as well as some patients and a storage room containing a Mondasian Cyberman, which eventually identified itself as Bill. Meanwhile, Missy was confronted by Razor, who threatened to kill her after she found that the ship originated from Mondas; Razor eventually revealed himself to be Missy's immediate previous incarnation, before the duo found the Doctor, Nardole and the Cyber-converted Bill in the conversion theatre, declaring that the "exodus" was, in actuality, the "genesis of the Cybermen". (TV: World Enough and Time) In the resulting fight, the Doctor was knocked out, but not before editing the Cybermen's definition of humanity to register life-forms with two hearts as human. Nardole quickly fled the hospital, unable to fight back against the two Masters, while Bill simply looked on, too distressed to do anything.

With Floor 1056 transformed into the Cyber Foundries, the Master and Missy danced together on the hospital roof, with Bill stood back afar. The Doctor soon woke, handcuffed to a wheelchair, and the two Masters gloated to him over his failure to save Bill or the people of the city from becoming Cybermen. Suddenly, an alarm on a broadcasting tower on the hospital sounded, as dozens of Mondasian Cybermen began attacking the hospital. Following the Doctor's revelation of his efforts to hijack the Cybermen's info-network before being knocked out, the Master and Missy began fighting off the Cybermen, but eventually freed the Doctor upon acknowledging that they couldn't fight off the entire army. Shortly after Missy knocked out the Master, the Doctor called Nardole with his sonic screwdriver, the latter arriving in a shuttlecraft from the floor's loading bay; however, as the Master began climbing aboard, the Doctor was severely electrocuted by a Cyberman before it was destroyed by the Cyber-converted Bill. Preventing the shuttle from leaving without her or the unconscious Doctor, Bill climbed aboard and the group blasted through hundreds of floors of the colony ship before they crashed on Floor 0507. As they emerged from the shuttle, Nardole encountered Alit, and said that they were going to need her help.

Back on Floor 1056, the Cybermen, now no longer controlled by the Master, began preparations for the final assault on the colony ship, and the eventual completion of Operation Exodus. As they began to upgrade themselves over the span of hundreds of years into radically more powerful forms – in an example of parallel evolution (TV: The Doctor Falls) – they eventually installed a Cyber-Planner on Floor 1056 to serve as their strategist and overall leader, as well as a number of Cybermats, and at least seven Mondasian Cybermen were evolved into CyberNeomorphs, including a Cyber-Leader and Cyber-Lieutenant. (PROSE: Alit in Underland)

Floor 0508
Following the shuttlecraft's crash-landing on Floor 0507, the Doctor, Bill, Nardole, the Master and Missy arrived at a large farmhouse, where the Doctor received treatment for his injuries. (TV: The Doctor Falls) The Master then explained to Nardole and Hazran, the leader of the floor's farming community, that he intended to travel to Floor 0508 to stop "the exodus" and the "scarecrows" (the children's name for the patients) and find a way to escape the colony ship; in truth, he actually intended to reverse the Doctor's edit to the Cybermen's definition of humanity and regain control of the Cyber-army. That night, alongside Missy, the Master returned to the crashed shuttlecraft and entered the walkways underneath Floor 0507 via the shuttle's crater. However, the duo were found by Alit, who had followed them from the farmhouse only to have a close encounter with one of the patients. Whilst exploring the walkways for an entry point to Floor 0508, the trio were pursued, and attacked, by the patient that Alit fled from on Floor 0507; Missy parried it long enough for the Master to reprogram it to respond to his voice commands, turning the patient – who Missy had begun referring to as "Topknot" – into the Master's slave. The group then descended into Floor 0508 via a service lift.

The Master, Missy, Alit and Topknot spent the next day riding on various forms of automated farming machines, eventually arriving at a large collection of storage silos for farming produce, where they encountered a group of six CyberNeomorphs, led by a Cyber-Leader and a Cyber-Lieutenant. Explaining that they had been tasked by the Cyber-Planner with capturing the two Masters for interrogation concerning the edit to the Cybermen's definition of humanity, the Cyber-Leader escorted the Master, Missy and Alit to some lifts and a storage cell guarded by another Cyberman. As the Cybermen tried to imprison the trio until the lifts arrived, Missy used her sonic umbrella to stun all the Cybermen whilst the Master killed the Cyber-Lieutenant with his laser screwdriver. When the Cyber-Leader rendered the Master unconscious, Missy and Alit escaped into a storage bay, pursued by two Cybermen. The Cyber-Leader then ordered another pair of Cybermen to prepare a swarm of Cybermats for attack.

Attempting to escape to a weather control tower nearby, Missy and Alit found some rats on the way, and were able to temporarily scramble the Cybermen's life-sign scanners by caging the rats around their necks so as to register as life-forms with three hearts. On the way, they found Topknot, who had not been detected by the other Cybermen, and assigned him to keep watch at the base of the tower. Inside, Missy hacked into the ship's systems, and after explaining to Alit that the Cybermen intended to attack Floor 0507 with the Cybermats so that they could weaken its residents and invade the solar farm more easily, she discovered and reactivated an old failsafe system in the Cybermats, trapping them back on Floor 1056; the failsafe system was originally integrated into the patients to stop them leaving the hospital mid-conversion, and had since been integrated into the evolved Cybermen and their technology. After hacking the weather controls to force a rainstorm outside, Missy, Alit and Topknot left to rescue the Master.

Using Topknot as bait for the Cybermen, Missy rescued the Master from his cell while Alit retrieved three pairs of rubber boots, and the group put them on before exiting the network of storage silos, only to be attacked by the Cybermen. In response, the Master fired his laser screwdriver at the steel deck of the floor, generating a huge electrical shockwave that destroyed the Cybermen; the two Masters and Alit survived due to their rubber boots insulating the electrical blast. Riding another service lift to a stable on Floor 0507, where they rode a horse and cart back to the farmhouse, Alit noted that Missy could have reactivated the failsafe system in the Cybermen themselves as well as the Cybermats, thereby preventing a future attack on Floor 0507, but Missy encouraged her to not mention it to anyone. Missy herself also noted that the only way to stop her predecessor's plans may be to kill him outright. (PROSE: Alit in Underland)

Preparing for war
Back on Floor 1056, the Cybermen continued to evolve over hundreds of years, eventually transforming into an army of three Cyberman variants; alongside the Mondasian Cybermen, (TV: The Doctor Falls) there were also several Cybermen identical to those of the Cyber Legions (TV: A Good Man Goes to War) and the Cyberiad. (TV: Nightmare in Silver)

Meanwhile, two weeks passed on Floor 0507 following the arrival of the Doctor, Bill, Nardole, Missy and the Master. By this point, the residents of the solar farm were under the leadership of Nardole and Hazran, having prepared defences around the farmhouse for an inevitable attack from the Cybermen. One night, Bill woke up in a barn after Hazran arrived with some blankets for her; with no recollection of how she had arrived on the floor or of what had happened to her on Floor 1056, Hazran simply told her that she had been put to sleep by the Doctor and that her appearance scared the children, hence why she was sleeping in a barn. Hazran then quickly left, also afraid of Bill.

The next morning, the Doctor, who had somewhat recovered from the Cybermen's attack on Floor 1056, explained to Bill what had happened to her, and that she had retained her individuality (TV: The Doctor Falls) due to the strength of identity she developed while living under the rule of the Monks on Earth. (TV: The Lie of the Land) After Bill accidentally destroyed the barn doors with her Cyber-gun, the Master escorted the Doctor and Bill to a nearby forest (the Doctor resisting the effects of regeneration along the way), where Missy had found the floor's lifts, which the Doctor intended to use to evacuate the children. However, when Missy called one of the lifts, the group were forced to destroy a Cyberiad-style Cyberman in a team attack when it emerged from the lift. Noting that the Cybermen now knew where they were, Missy argued that the four of them could travel to Floor 0000 and escape in the Doctor's TARDIS, but the Doctor explained that doing so was too dangerous as the time dilation meant the Cybermen would have thousands of years to formulate a plan to stop them all escaping.

By the time the Doctor, Bill, Missy and the Master returned to the farmhouse with the dead Cyberman, the Cybermen – having spent an unknown amount of time upgrading even further so as to achieve flight capabilities – sounded an alarm to the humans of Floor 0507 before initiating their attack phase, with hundreds of Cybermen of all three variants taking off from Floor 1056, blasting through hundreds of floors (such as Floor 0900) to reach Floor 0507.

As final preparations began on Floor 0507, the Doctor and Bill found a sealed service duct connecting to the farmhouse's cellar, which Bill promptly burned open with her Cyber-gun. Outside, Nardole used a laptop to hack into the fuel systems underneath the solar farm, and after some tests, created the impression that the rifles could fire highly explosive rounds, when in truth Nardole was simply causing powerful controlled explosions by igniting the fuel lines that corresponded to where the rifles were being fired to. The Doctor explained that they could use this to trick the Cybermen into believing that the humans were far more dangerous than they initially seemed.

Meanwhile, inside the farmhouse, Missy proposed to the Master that they could both travel to Floor 1056 and escape in the latter's TARDIS, prompting an argument between the two where the Master explained that he destroyed his dematerialisation circuit upon trying to escape the colony ship when he first arrived. In response, Missy told the Master of a time where a "very scary lady" pushed her against a wall and made her promise to always carry a spare dematerialisation circuit on hand; at the same time, Missy also pushed the Master against a wall, revealing that her memory was from when she was her predecessor, and the "scary lady" was Missy herself.

That night, as the Cybermen flew ever closer to Floor 0507, the adult farmers were positioned at various points around the farmhouse, rifles aimed through walls of sandbags. With the children hiding under their beds in their bedrooms, Nardole sat with Hazran downstairs when Bill walked in; Hazran, mistaking Bill for a regular Cyberman, shot her before Nardole explained that it was Bill. Hazran apologised to Bill, the latter promptly leaving. Bill then found the Doctor outside, sat in a rocking chair with a rifle in hand, shortly before the Cybermen began bursting through the ground. Estimating that the Cybermen would attack in a maximum of ten minutes, the Doctor was greeted by Nardole, Hazran and Alit. The Doctor then gave Alit an apple, stating that her role was to use "humanity's first weapon" against the Cybermen.

Shortly before the attack, the Doctor found Missy and the Master, who enquired as to the Doctor's plan. The Doctor stated that he intended to evacuate all the children and most of the adults to Floor 0502, a deck located five levels above Floor 0507 that contained another solar farm. The Master mocked the Doctor, noting that the Cybermen would simply continue hunting the humans even if they evacuated. When the two Masters began leaving, the Doctor angrily explained to them that he wasn't trying to "win" against the Cybermen, but that he was trying to do what was right: trying to help a tiny band of humans survive despite the odds rather than simply leave them to die. However, his attempts to persuade the Master and Missy to stay and help failed, although Missy thanked the Doctor for trying to rehabilitate her.

The battle of Floor 0507
The Cybermen commenced the attack, marching to the farmhouse on all sides, determined to capture the humans, in particular the children, for conversion. Several dozen Cyberiad-style Cybermen were confronted by Alit, who threw the apple the Doctor gave her at the Cybermen before running off. Shortly afterwards, Nardole ignited the fuel lines directly beneath the Cyber-patrol, destroying them in a huge explosion. Alit then met with him, and the pair returned to the farmhouse. Meanwhile, in the forest, the Master and Missy evaded several Cybermen on their way to the lifts, with explosions occurring nearby.

Back in the farmhouse, Nardole explained to Hazran how he was attacking the Cybermen, before quickly triggering another explosion. The Doctor and Bill then entered, the former explaining that in any second, the Cybermen, having lost a significant number of troops, would regroup and change their strategy, registering the humans as a military target before resuming their attack with the intent of killing the humans, deeming them too dangerous to capture and upgrade; however, this also meant that they would stop actively tracking the children, giving the humans a chance to escape through the service duct in the farmhouse cellar to the lifts.

As the Cybermen withdrew, Hazran began rounding up all the children in the cellar, and the Doctor explained to Nardole that he was to lead the evacuation to Floor 0502; the pair had a brief argument, during which the Doctor downloaded all of Nardole's hacking software into his sonic screwdriver. Eventually, the Doctor convinced Nardole that between the two of them, Nardole would be much better at looking after the humans for the rest of their lives than the Doctor, who intended to stay behind and hold off the Cybermen long enough so that the humans could evacuate, shortly before igniting all the remaining fuel at once to destroy as many Cybermen as possible, at the cost of the Doctor's life. Bill also refused to join the evacuation, choosing to assist the Doctor in his final stand, preferring to die defending innocent people than live on as a Cyberman. Speechless, and with time running out, Nardole payed his goodbyes to the Doctor and Bill before leaving for the cellar to lead the evacuation.

In the forest, the Master and Missy, having reached the lifts, prepared to travel to the Master's TARDIS on Floor 1056. However, Missy pulled him into a hug, and after complimenting her predecessor and noting how she would always miss being him, stabbed him with a knife hidden in her sleeve. Missy helped the Master to the lift, explaining that his wounds were precise enough that the Master had more than enough time to escape in his TARDIS. After explaining that she intended to stand with the Doctor against the Cybermen, the Master, enraged, fired his laser screwdriver at Missy on its maximum setting, preventing her from regenerating. The pair then laughed maniacally at the irony of their "perfect ending", shortly before the Master hit the lift's call button, returning to Floor 1056. Missy then slowly laid to rest amongst some flowers, seemingly dying.

Outside the farmhouse, the Doctor and Bill heard the sound of the Cybermen's alarm, as they prepared to attack on the front and back respectively. After a final conversation between the pair, during which Bill joked about her sexuality – reminding the Doctor that her humanity was still present – the Doctor and Bill left for the forest. As he triggered numerous explosions in the forest, destroying several Cybermen, the Doctor recited some of the many worlds where he had defeated the Cybermen, but was eventually shot by a Mondasian Cyberman, who fired at him enough times to bring him to his knees, his regeneration imminent. Before he could either regenerate fully or be killed by the Cybermen, the Doctor ignited all the remaining fuel underneath Floor 0507, destroying the remaining Cybermen in a gigantic explosion.

Aftermath
Following the destruction of the Cybermen on Floor 0507, the Doctor, severely wounded, observed the last few explosions before seemingly dying, saddened by the lack of stars in the sky. Sometime afterwards, the Cyber-converted Bill, scorched and barely functioning, found the Doctor's body in what remained of the forest, the whole of Floor 0507 having been reduced to nothing more than an uninhabitable wasteland. As she began to cry, however, Heather materialised from a rain puddle, having reached Bill (TV: The Doctor Falls) due to the former leaving Bill with her tears. (TV: The Pilot) Heather transformed Bill into a creature of sentient oil like herself, causing Bill's Cyber-form to collapse to the ground, the final casualty of the battle. The two then kissed, before returning the Doctor's body to his TARDIS on Floor 0000. Heather then placed the TARDIS in flight, before she and Bill prepared to leave; shortly before, Bill left the Doctor her tears, quoting his earlier phrase "when there's tears, there's hope". Bill and Heather then left the TARDIS to begin exploring the universe themselves.

Following this, the Doctor's regeneration resumed as he began experiencing flashbacks of numerous former companions, before a flashback of Missy finally woke him up. As he began saying some of his past incarnations' last words, he halted his regeneration once again, refusing to change. Upon exiting the TARDIS, he prevented his regeneration again only to be discovered by the First Doctor, (TV: The Doctor Falls) the Twelfth Doctor realising that he had landed in Antarctica on Earth shortly before he regenerated for the first time. After both incarnations had one final adventure, the Twelfth Doctor regenerated into the Thirteenth Doctor. (TV: Twice Upon a Time)

After the evacuation to Floor 0502, Nardole waited outside one of the lifts. Alit suggested that the Doctor and Bill might arrive, but Nardole dismissed the thought. He then explained to Alit that the few remaining Cybermen on the ship would likely take some time to calculate a new plan before they attacked the humans again, and although he didn't initially have a plan, Nardole assured Alit that he would have one soon. A young girl then arrived and told Alit and Nardole that Hazran had prepared some food for them, and the group left, the children telling Nardole that Hazran like him. (TV: The Doctor Falls) Nardole and the humans continued to fight the Cybermen on a near–daily basis, during which he began contacting Bill via space-time telegraph. At one point he also fell nearly thirty feet in the banana meadow, breaking his leg and having to rely on the children to push him around in a wheelbarrow. (WC: The Best of Days)

Eventually, Nardole and the humans were able to end their conflict with the Cybermen and reduce their attacks to annual Cybermat incursions every spring. Nardole spent the rest of his life onboard the colony ship before dying at the age of 728, during which Nardole had six wives, two of whom he was married to at the same time. At some point, the Testimony Foundation arrived at the colony ship and saved the memories of Nardole and his six wives so that they could live on as glass avatars; Nardole later claimed to the Twelfth Doctor and Bill that he was taken in by accident, the Foundation mistaking him for a human, but was allowed to live on after he sarcastically encouraged them to "be cruel" and not save his memories. (PROSE: Twice Upon a Time)

Upon returning to Floor 1056 after being mortally wounded by Missy, the Master left the colony ship in his repaired TARDIS before regenerating into Missy, losing all memory of his time on the ship. (TV: The Doctor Falls) Meanwhile, Missy was able to survive her predecessor's attempt to kill her by creating an Elysian field to "kick start a new regeneration cycle". The process of cryogenetic extraction destroyed her body but retained a copy of her consciousness. Inspired by the Doctor's good nature and his attempts to make her a better person, Missy regenerated into an incarnation that she called "the Lumiat". (AUDIO: The Lumiat)

On Floor 0000, sometime after the Doctor, Bill and Heather had left in the Doctor's TARDIS, Jorj woke up with a sore head after the Doctor knocked him unconscious before he left with Nardole and Missy for Floor 1056. As Jorj completed one of his many ship logs, an alarm sounded, alerting him that a critical systems failure had caused a massive explosion on Floor 0507. Observing a number of life-signs moving up the ship, Jorj simply hoped that his status as a non-human would keep him safe from anyone, or anything, left on the ship. (PROSE: Jorj)

Nave colonial (World Enough and Time)