닥터 후 시리즈 9

Clara discovers Santa Claus on her rooftop. The Twelfth Doctor arrives and takes her away in the TARDIS. At the North Pole, a group of scientists work on trying to save their fellow base personnel who have been taken over by Dream Crabs, alien crabs that induce a dream state while devouring a person's brain. The Doctor and Clara arrive at the base and come under attack from the crabs, only to be rescued by Santa. Clara is slowly devoured by a crab. The Doctor enters Clara's dream with another crab to wake her. Clara and the Doctor wake up, which kills the crabs devouring them. The Doctor realises everyone is in a multi-layered dream, with Santa being part of it. They escape when they dream that Santa is flying them home. One by one they wake up until only Clara is left. The Doctor awakens and removes the crab from Clara, only to discover that Clara is now an elderly woman. Santa appears and the Doctor realises he is still dreaming. Waking up, the Doctor frees Clara, now a young adult, from the crab. He asks Clara if she wants to rejoin him aboard the TARDIS; she accepts.

The Doctor attempts to rescue a boy on a battlefield, but upon discovering that the boy is a young Davros, abandons him and goes missing. On Earth, Clara is summoned by UNIT when all of the world's aircraft freeze in the sky, and they discover Missy is causing the phenomenon. Missy has the last will and testament of the Doctor, called his confession dial, and tells Clara that they must search for him. They trace him to Essex in 1138, where he has spent three weeks throwing a party. When Clara and Missy reunite with the Doctor, an agent of Davros called Colony Sarff arrives and explains that the elderly Davros wishes to see the Doctor, before taking the three to a hospital space station. Clara and Missy discover the station is a building on an invisible planet, but as the landscape reappears, Missy identifies the planet as Skaro, the home planet of the Daleks. They are captured by the Daleks, who appear to kill them and destroy the TARDIS. The Doctor returns to the battlefield, holding a Dalek weapon, preparing to save his friend.

Using Dalek energy, Missy was able to power her teleporter for her and Clara to escape. The two attempt to find the Doctor, going through the sewers, which are filled with decaying Daleks. They successfully kill a Dalek and empty its case to disguise Clara inside of it. Meanwhile, the Doctor comforts the dying Davros, feeling compassion for him having abandoned him as a boy in the past. The Doctor uses a little regeneration energy to power Davros' life support, which is also connected to every Dalek. This turns out to be a trap, and begins draining the Doctor to regenerate Davros and the Daleks. Missy saves the Doctor, and the energy also restores the dying Daleks, who wish to destroy the functional Daleks. While escaping, the Doctor and Missy encounter Clara's Dalek. Missy tries to trick the Doctor into killing her, but fails after the Dalek asks for mercy. Missy escapes. Using his new sonic sunglasses, the Doctor summons the TARDIS, which also had avoided destruction by its automated systems. The Doctor then returns to the battlefield, where he does not kill Davros, but destroys the mines to free him, and then helps him home.

The Doctor and Clara arrive in an underwater base in 2119. The military team there have discovered an alien craft in the ruins of a submerged Scottish town with glyphs scratched in its inside walls, but Commander Moran was killed upon its discovery. At night, the ghosts of Moran and a Tivolian appear. The Doctor and the others attempt to capture the ghosts and understand what they want, and find out that they are repeating coordinates. They find an unopenable stasis chamber at the church where the coordinates led. The Doctor concludes that the ghosts are being used to send a call to the location. The Doctor decides to go back to before the flood and find out the true meaning behind the signal. Clara, acting commander Cass, and crewmember Lunn are separated from the Doctor and crewmembers O'Donnell and Bennett. Shortly after the Doctor, O'Donnell, and Bennett leave in the TARDIS, Clara spots a new ghost in the lake, only to discover that it is the Doctor.

The Doctor, Bennett, and O'Donnell land in 1980. They discover that the Tivolian, Prentis, is still alive, the writing has not yet been scratched into the wall, and Prentis landed on Earth to bury his former enslaver the Fisher King. The Doctor contacts Clara in 2119, who tells him the Doctor's ghost is mouthing their names. The ghost releases the others from the Faraday cage. In 1980, the Fisher King awakes, killing Prentis and writing the glyphs on the wall. O'Donnell is killed, confirming the suspicion that the Doctor's ghost is saying the order in which they will die. Attempting to save Clara, the Doctor confronts the Fisher King. He tells the Doctor the ghosts created by the glyphs will send a signal that will draw an armada. The Fisher King is drawn away from the chamber, and the Doctor destroys the dam wall, flooding the town. The stasis chamber opens in 2119 to reveal the Doctor inside; his "ghost" is a hologram, programmed by the Doctor. The hologram lures the ghosts back inside the Faraday cage. The plot is a bootstrap paradox—the Doctor programmed the ghost to say the names because that is what the ghost's message said.

After being captured by Vikings, the Doctor and Clara are brought to their village. A race of conquerors called the Mire kill the village's warriors and drain them of their testosterone and adrenaline. The Doctor and Clara begin training the villagers for battle after a woman from the village called Ashildr declares war on the Mire. The next day, the Mire invade, and the Doctor steals a helmet for Ashildr to use. She broadcasts a vision of a dragon into the Mire's other helmets and forces them to retreat, but she dies from the use of her helmet. The Doctor and Clara mourn, but then the Doctor realises his face^{[N 1]} is a reminder that he does not have to follow the rules of time and space. He uses a Mire medical chip to bring Ashildr back to life. This makes her immortal. He provides the second chip in hope she would give it to one she cares for.

The Doctor is alone and on the trail of an alien artefact in 1651 England. He interrupts Ashildr, now calling herself "Me", attempting to rob Lucie Fanshawe. Throughout her immortal life, she has lost many memories, and now isolates herself as to not lose loved ones. Me and the Doctor steal the artefact from Lucie's house. The Doctor meets Me's ally Leandro, a leonine alien stranded on Earth who uses the artefact to open portals into space. In return for Me tricking the Doctor into helping him, Leandro has agreed to let her come with him to travel the galaxy. However, in order for the portal to be activated, the artefact requires another person's death. Me kills the outlaw Sam Swift, opening the portal. Leandro reveals that his intent is to assist his people in invading Earth. When Me rediscovers her humanity after seeing spaceships attack the crowd, she uses the medical chip to save Swift, closing the portal. Leandro's people kill him for his failure. Afterwards, Me says that she will look after those that the Doctor leaves behind.

A peace treaty has allowed 20 million Zygons to remain on Earth, peacefully living out as disguised humans. Two versions of the scientist Osgood, a human and a Zygon duplicate, kept the peace until one of them died and the other disappeared. The Doctor leaves the Osgoods the Osgood Box to be used as a last resort. In New Mexico, a Zygon splinter group kidnaps Osgood. In London, a splinter group member called Bonnie takes over Zygon High Command. At the block of flats where Clara lives, Clara is knocked unconscious and hidden in a pod underground. Bonnie takes Clara's place. Bonnie tricks UNIT troops into going to a series of underground tunnels, which many other lifts across the city are connected to. The troops are killed by the splinter group when they attempt to escape. Kate Stewart is attacked by a splinter group member disguised as a sheriff while investigating Osgood in New Mexico. The Doctor rescues Osgood from captivity in Turmezistan and the two set off back to London. A Zygon captured and taken on board the plane tells the Doctor the invasion has already taken place. Bonnie fires a missile at their plane.

The Doctor and Osgood escape the plane before it is shot down. Within Clara's mind, Bonnie learns that the Osgood Box is held in UNIT's Black Archive. Against the wishes of the Zygons who are not aligned with the splinter group, Bonnie intends to start a war against humanity by using the Osgood Box to unmask 20 million Zygons on Earth. Clara telepathically breaks through Bonnie's control and alerts the Doctor to her whereabouts. Kate, having survived the encounter in New Mexico, joins the Doctor and Osgood. The three arrive at the Black Archive where Bonnie has found there are two Osgood Boxes, one which would either unmask the Zygons or make their human forms permanent, and the other which would destroy either every Zygon or everyone in London. When Bonnie and Kate prepare to activate the boxes, the Doctor talks them out by explaining the Boxes are a means to assure peace because of the consequences of declaring a war. Bonnie realises the boxes are empty as a ploy. The Doctor wipes Kate's memories to keep the peace treaty. Bonnie calls off the splinter group and says they will live peacefully. Bonnie becomes the new Osgood duplicate.

A four-person rescue team from Triton arrives at Le Verrier Lab, a space station in the 38th century in orbit around Neptune which has fallen silent. They meet the Doctor and Clara, who claim to be assessors. They then meet Gagan Rassmussen, the last survivor of Le Verrier and creator of large pods called Morpheus, which reduces the time a person sleeps to allow them to work more but also mutates the rheum in the corner of the eye into a carnivorous life form called the Sandmen. Chopra, Deep-Ando, and 474 are killed during their escape. Rassmussen plans to use the rescue ship to return to Triton and release Morpheus there with a Sandman, which he says is now spread by spores. The Doctor destroys the gravity shields, sending the station and ship into Neptune. The Doctor comments that the inconsistencies in how Morpheus is spread seems to be contrived like a story. The Doctor, Clara, and Nagata escape in the TARDIS. Rassmussen, revealed to be a Sandman himself, orchestrated the events to use footage collated from people's vision to create a video that people would watch to transmit the Morpheus signal across the Solar System to create more Sandmen.

The Doctor and Clara receive a phone call from Rigsy, who informs them of strange numbers that have appeared on the back of his neck that are counting down with no memory of how he got it. After examining him, they trace his movements to a trap street in present-day London that houses extraterrestrial refugees. They then discover Rigsy was sentenced to death by Me,^{[N 2]} the street's mayor, for murdering an alien called Anah and that Rigsy will be killed by an alien raven when the tattoo, known as a Chronolock, reaches zero. Clara discovers that the Chronolock can be transferred to a willing recipient and takes it from Rigsy, believing that Me will spare her, buying them more time. The Doctor realises from the medical data in the stasis pod Anah is stored inside that Anah is still alive; Me made a deal with an unknown party to have the Doctor transported far away to keep the street safe. As the Chronolock has been passed on to Clara, Me cannot remove it and Clara cannot be saved. Clara pleads with the Doctor not to take revenge for her. The raven kills Clara, and the Doctor is teleported away.

The Doctor teleports into a chamber in a castle. He is followed by a creature which intends to torture him, but discovers that after giving a confession of some kind, the creature will temporarily retreat and the castle will shift its form. The Doctor seeks to escape, and investigates clues that direct him to a particular room, in which he finds a wall made of Azbantium, a mineral harder than diamond. He determines that he has already been in the castle for 7000 years. Understanding what this and other clues imply, he tries in vain to break the wall with his fist, but the creature appears and mortally wounds him. He crawls back to the room he appeared in, and sacrifices himself just as the configuration of the castle resets, rematerializing a copy of himself exactly as he originally teleported in. By exactly repeating this entire cycle of events innumerable times, the Azbantium wall is eventually weakened and he breaks through.^{[N 3]} Stepping through the breach, the Doctor sees he was inside his confession dial all along, and is now on Gallifrey, eons from now. He tells a nearby child to go to the city and inform the Time Lords he is on his way and that he knows what they did.

Aided by the Gallifreyan military, the Doctor usurps and exiles Lord President Rassilon. Now the new President, the Doctor learns that Rassilon imprisoned him in the dial to force him to confess about the Hybrid, which is prophesied by the Time Lords to stand in Gallifrey's ruins and unravel the Web of Time. The Doctor has the Time Lords retrieve Clara from her timeline at the instant of her death, ostensibly so the Doctor can consult her about the Hybrid. The Doctor escapes Gallifrey with Clara with a TARDIS stolen from the workshops under the Capitol, attempting to take her far away enough that she will return to life, despite this potentially damaging time. At the end of the universe, the Doctor encounters Ashildr^{[N 2]} in Gallifrey's ruins; the two conclude the Hybrid is the Doctor and Clara together. The Doctor decides to remove Clara's memories of him to prevent the Time Lords from finding her, but Clara alters the device so it will affect the Doctor. The Doctor wakes in the Nevada desert where his own TARDIS has been moved. Clara, travelling with Ashildr, begins her trip to Gallifrey in the TARDIS stolen from Gallifrey to return to her death.

The Doctor is on the planet Mendorax Dellora in 5343, where due to a case of mistaken identity he is recruited by his former companion and wife River Song to assist her in removing a diamond from the head of King Hydroflax after his maligned attempt to steal it. Surprised that River cannot identify his newest face, the Doctor struggles to break the news to her while learning how she acts on her own – and how many other lovers she has had. The Doctor and River bring the head of Hydroflax to the starship Harmony and Redemption to sell it, and a series of events causes River to discover the Doctor's identity. The starship is caught in a meteor strike and crashes into the planet Darillium, where the Doctor and River are fated to have their final date together before River dies meeting a younger Doctor. Having deliberately held it off for as long as possible, the Doctor finally decides to give in and arranges for a restaurant to be constructed on the planet. The Doctor and River then have their final date together, which lasts for 24 years – the span of a night on Darillium.