The Age of Steel

Having escaped from the alternate universe's Pete Tyler's home from an army of Cybermen, the Doctor is able to disable the robots, saving his group. Insisting to Pete that everyone inside his home, including his wife Jackie, is likely dead, the Doctor directs Pete, Rose, Mickey, and the Preachers, including Mickey's alternate universe counterpart Ricky. Jake, and Mrs. Moore, to get back to London to warn the authorities. As they flee, Pete explains that he was working with Lumic, the man that has created the Cybermen, only to learn of his plans and provide that information to the Preachers. Meanwhile, Lumic orders the Cybermen to bring those humans under control of his EarPods to the Battersea Power Station for conversion.
When they reach the city, the group discovers Lumic's zeppelin moored near the power station and make towards it; Ricky is killed by the Cybermen during their incursion. After inspection the station, the Doctor determines they must destroy the EarPod transmitter, located on the zeppelin. The group splits up: Mickey and Jake to board the zeppelin, Pete and Rose to pose as affected humans to try to disrupt the conversion process, and the Doctor and Mrs. Moore to find their way to Lumic. Pete and Rose are captured by the Cybermen when one, the converted Jackie, catches sight of them. Though Mrs. Moore is killed by a Cyberman, the Doctor discovers that each unit contains an inhibitor signal to prevent their human side from taking over, and determines that if he can disable the signal, the converted Cybermen will likely kill themselves over their moral dilemma. However, he is captured by the Cybermen before implementing his plan.
Taken to Lumic's office, the Doctor discovers the Cybermen have captured Pete and Rose, and they have forcefully converted Lumic into their leader. When Mickey and Jake successfully disable the transmitter, Lumic reveals they will simply take the humans by force. The Doctor, aware that Lumic's office is under surveillance by Mickey and Jake, subtly attempts to ask for the inhibitor code. Mickey eventually recognizes the Doctor's plan, locates the code in the zeppelin computers, and sends it to Rose's phone. The Doctor plugs the phone into the computer systems, causing the inhibitor signal to drop and sending the army of Cybermen into despair. As the conversion facility begins to go up in flames, the group escapes to the zeppelin, leaving Lumic to die.As the city recovers, the Doctor, Rose, and Mickey return with Jake and Pete to the TARDIS, the power cell sufficiently charged to allow the TARDIS to return to the proper dimension. However, Mickey reveals that he plans to stay with Jake and Pete in the alternate universe, as to take care of Ricky's grandmother and continue the Preacher's fight and destroy Lumic's other factories. After the TARDIS' departure, Mickey recounts to Jake how he once "saved the universe with a big yellow truck".

Rise of the Cybermen

As the Doctor and Rose reminisce about a past adventure while the TARDIS is in-flight, Mickey begins to feel upset that the two take him for granted. However, before they can comment, the TARDIS is rocked by a huge explosion and goes dark. The Doctor determines that they have fallen out of the time vortex into the void, and have landed somewhere, but that the TARDIS appears dead. They find themselves on Earth in London, but in a parallel universe. Zeppelins fly in the skies and Rose spots an advertisement featuring her father Pete Tyler as a successful business leader, when in her own universe Pete has died. The Doctor notes that the TARDIS can only operate on power from its own universe, and spots a dim but glowing power cell in the bowels of the ship. The Doctor breathes into it, giving away 10 years of his life but allowing the cell to start recharging, a process that will take about 24 hours after which they should be able to return to their universe. Given the wait, Rose and Mickey decide to go and check on respectively Pete and Mickey's grandmother, both alive in this universe. The Doctor, worried for both, ends up chasing after Rose.
The Doctor and Rose discover that most of the population of this universe wear special "EarPods", devices that, when activated by a signal, download massive amounts of news and information directly to the wearer's brain, information that is also received by Rose's mobile phone. They learn that the EarPods as well as Pete's company are owned by the powerful John Lumic, owner of Cybus Industries, who is presently failing to gain approval from the Ethics Committee of Great Britain for his "ultimate upgrade": a method of sustaining the human brain indefinitely within a cradle of copyrighted chemicals and allowing its impulses to be bonded onto a metal exoskeleton. Lumic secretly has been capturing homeless people and putting them to work in his Battersea Power Station factory using the EarPods as methods to control the homeless. Having been denied permission by the President of Great Britain, Lumic tells his right-hand man Mr Crane to begin the upgrade process. Crane drives an International Electromatics lorry and kidnaps more homeless people, but instead of just fitting them with EarPods, he orders them into a room filled with cutting and other machinery which transforms them into the new prototypes.
Mickey arrives at his grandmother's house to find her still alive, but before he can get acquainted with her, he is grabbed by people in an unmarked van and taken to a country house. One of his abductors, Jake, who calls him "Ricky", tells him that he is the most wanted person in Great Britain, and that they have evidence of Lumic's dealing with the homeless people. When they arrive at the base, the real Ricky, Mickey's counterpart in this universe, is there, and explains he is the leader of the "Preachers" who reject the EarPods and have been tracking Lumic's actions. After clearing the confusion between the existence of Ricky and Mickey, the group learns of pending action by Lumic and, with Mickey in tow, make towards Pete Tyler's estate.
The Doctor and Rose arrive at Pete's estate and learn that there is a large party there that night, where the President of Great Britain and Lumic will be present. The Doctor and Rose pose as part of the serving staff to investigate, and learn that this Pete and Jackie Tyler are childless but have a pet terrier called Rose. Rose meets both Pete and Jackie and learns that they have just separated secretly. As the party gets underway, Lumic presents his plans for his prototype, which the Doctor recognises right away. Before he can act, the partygoers hear the sound of troops surrounding the building, an army of metal men, which the Doctor tells Rose are Cybermen. As the Cybermen break through the windows, Lumic explains that they have been selected to be upgraded to "Human.2", and that every human will receive a compulsory free upgrade. The President resists, and is electrocuted by a Cyberman who informs them that this is the only alternative to conversion. As Jackie flees into the basement with a Cyberman in pursuit, the Doctor, Rose, and Pete jump out a window and find the Preachers there, firing their ineffective weapons at the Cybermen. As the episode closes in a cliffhanger, the Doctor, Rose, Pete, Mickey, Ricky, and Jake are surrounded by the Cybermen who, deeming them incompatible for upgrading, announce they will be deleted and move in for the kill.

The Girl in The Fireplace

The TARDIS arrives in a derelict spaceship, which is fully functional yet motionless and without a crew. The travellers —the Doctor, Rose Tyler, and Mickey Smith— are further baffled to find an 18th century French fireplace. Looking through the fireplace, the Doctor sees a young girl. He asks who she is, and she replies that her name is Reinette, and that she lives in Paris in the year 1727. The fireplace is a "time window", allowing direct access to another time and place; passing through the window, the Doctor arrives in Reinette's bedroom, although months have passed here, rather than mere seconds in the Doctor's time. Examining the room, the Doctor discovers a nightmarish ticking humanoid under Reinette's bed. The Doctor tricks the creature back through the time window to the spacecraft, where he and his companions learn that it is actually an android made of intricate, beautiful clockwork. Returning to Reinette's bedroom, the Doctor finds that she is now a young woman. She remembers him, and her charm and intelligence entrances the Doctor; they kiss, but she runs off to answer a summons for "Mademoiselle Poisson". The Doctor realises she is Madame de Pompadour (the mistress of King Louis XV), a historic figure he admires greatly.
Returning to the ship, the Doctor and his companions find several additional time windows at various locations throughout the ship, each leading to a different moment from the life of Madame de Pompadour. In one of them, the Doctor sees another clockwork creature menacing her. Stepping through the time window, he defends Reinette. Obeying her orders to explain itself, the clockwork creature tells her that the spaceship was damaged in an ion storm; the maintenance androids did not have the parts necessary to repair the ship, and killed the crew to use their organs for parts. One more part is required for the ship to be fully functional: Reinette's brain. Seeking more information on the motivation of the clockwork androids, the Doctor reads Reinette's mind, but is startled to find that she can read his as well, and has enormous empathy for his loneliness. Rose and Mickey are taken captive by the androids, but rescued by the Doctor (who returns blind-drunk from a party Reinette took him to, claiming to have invented the banana daquiri), who has discovered that the creatures are trying to open a time window into Reinette's life at the age of 37. At that age, the literal-minded androids believe Reinette's brain will be compatible with the ship's 37-year-old systems. The clockwork androids appear at a costume ball, forcing Reinette and the rest of the guests into the ballroom. At one end of the room is an enormous mirror, which is actually a time window; the Doctor and his companions can see through it, but cannot pass through without smashing the window; this would break the connection.The creatures threaten to decapitate Reinette, but the Doctor crashes through the mirror to save her, although he believes he has stranded himself in Versailles in the year 1758. The clockwork androids give up and shut down when the Doctor tells them that they have no way to return to the ship to carry out their mission. Reinette reveals that she had her fireplace moved to Versailles, hoping that the Doctor would return; the Doctor uses the window to return to the ship, and tells Reinette to pack a bag and choose a constellation to visit with him. When the Doctor returns to the fireplace, however, he finds Reinette is not there to meet him, having died in the six years since the Doctor's last visit. King Louis XV gives the Doctor a parting letter from Reinette, and the Doctor returns alone to the TARDIS. In the letter, Reinette expresses her hopes that the Doctor will return quickly, asking him to hurry as her days grow short, referring to him as "my love" and her "lonely angel". The Doctor returns the letter to his pocket, watching on the TARDIS screen as the fireplace goes dark and the time window is closed forever. The TARDIS vanishes from the derelict spaceship with the companions perplexed as to why the ship wanted the brain of Madame de Pompadour over anyone else's to complete its repairs; the Doctor puts this down to damaged and garbled memory banks. However, as the now-lifeless ship drifts through space, the camera reveals that the ship's name is the SS Madame de Pompadour.

School Reunion

Mr. Finch, the headmaster of Deffry Vale School, has been changing the school to improve the students' performance; his changes include free lunches with special chips. The Doctor, under the alias "John Smith", is undercover as a science teacher in the school and is shocked by the uncommon intelligence of the students. His companion, Rose Tyler, is working undercover in the school's cafeteria. Both the Doctor and Rose relate the mysterious events around the school to the chips: Rose observes that the chip oil has an adverse effect on the other kitchen staff, while the Doctor notes that the chips themselves are making children more intelligent.
The higher-than-average intelligence of the children has aroused media attention - in particular, the attention of investigative journalist Sarah Jane Smith. While at first the Doctor feigns ignorance, when Sarah Jane discovers the TARDIS during the night, he is forced to admit his identity. Sarah Jane meets Rose and Mickey, much to the chagrin of Rose. As they search the school, they find thirteen bat-like creatures asleep in Finch's office. Sarah Jane reveals a battered, inactive version of K-9, which - once repaired - identifies the chip oil as Krillitane oil. Rose, who was unaware he had past travelling companions and thought that she had "something special" with the Doctor, confronts him; he replies sadly that, while she can spend the rest of her life with him, he cannot spend the rest of his life with her.
The following day, the group returns to the school to investigate further. The Doctor confronts Mr. Finch, who confirms that he and the others are Krillitanes - a composite species that takes desirable attributes of the species they conquer. He attempts to subvert the Doctor, without success. Meanwhile, Sarah Jane and Rose try to unlock the programming on the school's computers; Mickey and K-9 remain in Sarah Jane's car for surveillance. With the Doctor's help, they discover that the computers - bolstered by the students' enhanced intelligence - are part of a Krillitane effort to solve the "Skasis Paradigm", a theory of everything. As the paradigm is nearly solved - which would allow the Krillitanes full control over time and space - the Krillitanes seal the school. Mr. Finch propositions the Doctor a second time, tempting him with the ability to save the Time Lords and override human mortality. With Sarah Jane's counseling, the Doctor refuses, and they run from Mr. Finch. Mickey crashes Sarah Jane's car through the school's doors and unplugs the computers, allowing the children to flee. The Doctor leads the Krillitanes to the kitchen; upon their arrival, K-9 opens fire on the oil barrels, destroying the Krillitanes, the school, and himself.
At episode's end, Rose, Sarah Jane, Mickey, and the Doctor are standing in the TARDIS. Sarah Jane declines a second chance of travelling in the TARDIS. Mickey says he would like to travel in the TARDIS instead, a suggestion of which Sarah Jane approves, much to the chagrin of Rose. She then asks Rose to stay with the Doctor and - if she needs help - to find her. Sarah Jane then gets a chance to part properly with the Doctor, who leaves her with a brand new K-9 as a parting gift.

Tooth and Claw

The Doctor attempts to take Rose to Sheffield in 1979 to see Ian Dury in concert, but ends up in the Scottish moors in 1879. They encounter a carriage carrying Queen Victoria, who has been forced to travel by roads to Balmoral Castle as a fallen tree has blocked the train line to Aberdeen, feared to be a potential assassination attempt. The Doctor poses as Dr. James McCrimmon using his psychic paper, and the Queen invites him and Rose to join her as they travel to the Torchwood Estate, a favourite of her late consort Prince Albert, to spend the night. The royal party is unaware that the Torchwood Estate has been captured by a group of monks from a monastery in St. Catherine's Glen led by Father Angelo, forcing its owner, Sir Robert MacLeish, to play into their ruse as they take the place of the house's servants and guards. The monks, having arranged for the fallen tree to force the Queen to the estate, have brought a man inflicted with a form of lycanthropy, hoping to pass its nature to the Queen and create a new "Empire of the Wolf".
The Doctor soon realizes the trap they have fallen into, and helps to save Rose, the Queen, and Sir Robert from Father Angelo's men and the werewolf by taking shelter in the estate's library, its wood coated with oil of mistletoe wood to stave off the beast. They study the library and discover evidence collected by Sir Robert's father, a polymath, and Prince Albert that indicate the werewolf is really the current form of an alien species that fell to earth in 1540 near the monastery, surviving by passing its lycanthropic form from human to human. The Doctor also realizes that the estate was designed as a trap for the werewolf, as by use of its strange telescope along with the Queen's Koh-i-Noor diamond, its cut fashioned by Prince Albert, they can force the werewolf to revert to human form and destroy the alien lifeform.Sir Robert sacrifices himself to allow the Doctor, Rose, and the Queen to prepare the telescope in the Observatory. They are able to trap the werewolf in the concentrated light of the full moon collected by the diamond. The transformed human being begs for the Doctor to kill him by increasing the power of the light concentration, which he obliges. As they recover, the Queen finds a small cut she believes came from a wood splinter, but the Doctor remarks to Rose that all her children will carry a form of haemophilia, and that perhaps this was simply a Victorian euphemism for lycanthropy. The next day, the Queen dubs the Doctor and Rose with royal titles before banishing them from the British Empire. The Queen is appalled and outraged by the unholy sort of lifestyle the Doctor and Rose share. In honor of Sir Robert's sacrifice and his father's ingenuity, she orders the creation of the Torchwood Institute to help defend England from further alien attacks.

New Earth

The Doctor uses the TARDIS to take Rose to the farthest point he's ever taken her, to the year five billion and twenty-three in the M87 galaxy. Humanity, after the destruction of the Earth, settled onto a very Earth-like world, called "New Earth", and Rose admires its beauty. The Doctor is summoned to "Ward 26" in a hospital in New New York through his psychic paper, and while he travels to the Ward, gets separated from Rose. In the Ward, the Doctor meets several humanoid feline nuns of the Sisters of Plenitude who are overseeing the patients, all who have incurable maladies but are somehow being cured by the Sisters. The Doctor recognises the Face of Boe, who reached out to "the Lonely God" in order to give him a message before he dies of old age. Meanwhile, Rose is brought to the basement of the hospital, where she is escorted by Chip to meet Lady Cassandra, who has survived from her previous encounter with the Doctor and has been watching the two since they arrived. Chip has been using the hospital facility to care for Cassandra, but Cassandra is suspicious of the methods used in the hospital and requires Rose's help. Rose tricked into stepping into a "psychograft" machine that allows Cassandra to implant her mind into Rose's, leaving her old "body" to die. Cassandra can read Rose's thoughts, and knowing of the Doctor's new form, goes to meet him as "Rose". The Doctor is suspicious of "Rose"'s actions, such as kissing him passionately or having knowledge of the advanced computer systems, but is more concerned on how the hospital can cure the incurable. He and "Rose" discover that the hospital houses hundreds of pods containing artificially-grown humans, forcibly inflicted with numerous diseases, such that the Sisters can discover their cures. The Doctor accuses the Sisters of the atrocity, though they insist it was necessary to deal with the influx of patients. The Doctor, believing that Rose's current actions are also a result of being a test subject, is suddenly knocked unconscious by a perfume gas and wakes up locked in one of the pods. "Rose" then approaches the lead Sister, Matron Casp, demanding payment for her to keep quiet about the hospital secrets, and when she is refused and threatened physically, releases the Doctor and some of the humans as a distraction, but the infected humans further release the others, and a zombie-like attack begins, with those infected trying to attack anyone healthy.
The hospital is put into quarantine as the Doctor, "Rose", and the remaining Sisters try to flee the lower levels. To help their escape, Cassandra is able to jump her mind between other bodies, including one of the infected humans, before jumping back to Rose, and learns that those humans feel a strong sense of loneliness of not being able to touch or be touched. Eventually, the Doctor and "Rose" reach Ward 26, and grab all the intravenous medical solutions; emptying them into a disinfectant shower, they are able to spray the mixture onto a group of the infected humans, who within moments become cured of their diseases. The Doctor encourages them to go and spread the cure to the other infected people, and soon, the attack is over. The police arrest the surviving Sisters, while the Face of Boe, who has also been cured, tells the Doctor that the message for him can wait until they meet for the third and final time, and then teleports away.The Doctor now orders Cassandra out of Rose's body. Cassandra transfers her consciousness to a willing Chip instead, but his cloned body begins to fail, and Cassandra accepts her impending, true death; the New Earth has no place for people like her and Chip. The Doctor does one last thing for Cassandra, taking her back to see herself on the last night someone had called her beautiful. "Chip" approaches the Cassandra of the past and tells her just that, and collapses into the younger Cassandra's arms as she comforts "him". As the older Cassandra finally dies, the Doctor and Rose silently leave in the TARDIS.

The Christmas Invasion

Following the events in The Parting of the Ways, the TARDIS returns to Jackie Tyler's estate flat shortly before Christmas, greeted by both Jackie and Mickey Smith. However, the man accompanying Rose Tyler from the TARDIS is unfamiliar to the two of them, and seems to be in bad health. Rose explains, as they get him dressed in bedclothes left by Jackie's beau (who has a habit of leaving pieces of fruit in the pockets) and into bed, that he is the Doctor, who has just undergone regeneration. With little else to do while the Doctor recovers, Rose and Mickey go Christmas shopping but are attacked by masked Santas. They escape safely to the flat where they find a Christmas tree in the flat; as they realize that Jackie didn't buy it, the tree comes to life, spinning fast enough to destroy anything in its path. Rose grabs the Doctor's sonic screwdriver and places it in his hand, asking the still-comatose Doctor for help; instinctively, the Doctor awakes and uses the screwdriver to disintegrate the tree, and recognizes that it was being controlled by more Santas outside the flat, though they transmat away before anyone can stop them. The Doctor collapses again, telling Rose that he is still regenerating and that the energy of his regeneration is luring the Santas, and whomever controls them, here, and he is put back to bed by the others.
Meanwhile, the "Guinevere One" space probe, launched under a United Kingdom program by Prime Minister Harriet Jones, is about to land on Mars, with a live television broadcast from the probe once it lands. However, unknowingly, the probe is swallowed by a giant spacecraft that makes its way silently to Earth. As the broadcast begins, the audience is rather surprised to find an alien face staring back at them. Harriet, along with the probe's team, learn that the broadcast comes not from Mars but 5000 miles above Earth. The alien speech is eventually translated, and the aliens are revealed to be Sycorax, and they are claiming the planet as their own, demanding surrender or "they" will die. Harriet sends a response back, telling them that she will not allow it and that they are armed, but the Sycorax ignore her, and instead activate a device that causes nearly one third of the world population to fall under their control, leading these people to stand precariously at the edges of the highest roofs they can find, as if ready to jump. The probe team learns that the commonality of those under the Sycorax control is that they all share the same blood type as a sample that was included on the probe. Realising they are overwhelmed, Harriet pleads through the television broadcast for the Doctor's help. Shortly after this, she along with members of the probe team are transmatted to the Sycorax ship, where the Sycorax demand that either one-half of the world's population be sold to them as slaves, or one-third of the population, those standing on the roofs, will die.
Rose and Mickey, who have been aware of what has occurred through Mickey's hacking skills, move the Doctor back to the safety of the TARDIS as the Sycorax ship takes position over London. The TARDIS is transmatted to the spaceship, unbeknownst to Rose and Mickey, and thus when they leave it, they are panicked to find themselves facing the Sycorax, resulting in a container of tea being spilt into the underbelly of the TARDIS control room near where the unconscious Doctor is lying and causing some sparks to form. Rose attempts to bluff the Sycorax in a manner similar to what she had seen the Doctor use before with the Nestene Consciousness, but they see through her claims. However, Rose's deception has allowed the Doctor to fully recover, thanks to the spilled tea, and he emerges from the TARDIS, fully regenerated. Asking the Sycorax to wait, the Doctor goes about greeting everyone, and discovers and disables the device that was controlling the humans by blood, which can only hypnotize humans. The hypnotic suggestions got the humans to the roofs but can not make them jump; the Sycorax threat was a bluff.
The Doctor challenges the Sycorax leader to a one-on-one battle over the fate of earth, which the leader agrees to. They sword fight, first inside the ship, then moving out onto its wing, with the Doctor appearing outmatched, and at one point, having his hand cut clean off. The Sycorax believes he has won, but the Doctor notes that as he is still within the first fifteen hours of regeneration, his body has incredible regenerative powers, and he is able to regrow his lost hand and take the advantage to defeat the leader. At sword point, he gets the leader to vow to never return to Earth again, and begins to return with the rest of the group inside the ship. However, the Sycorax leader attempts to attack the Doctor from behind; but the Doctor throws a satsuma found in the bedclothes he's wearing at a control button that causes the area of the ship's wing to disappear, dropping the Sycorax leader to Earth.
The Doctor addresses the Sycorax and forbids them to ever return to Earth. The Sycorax are to go home and warn other aliens species that the Earth is off-limits to them, and that the Earth is defended.
The Doctor returns all the humans back to Earth and watch as the Sycorax ship moves away. Harriet receives a call and learns that "Torchwood is ready", and subsequently orders it to initiate an unrevealed process. (Torchwood was only previously mentioned in the episode Bad Wolf and only referred to as "they" in this episode.) To the Doctor's horror, five powerful energy beams from across London converge on the Sycorax ship and destroy it. Harriet justifies it as needed to be able to defend the Earth from other hostile aliens when the Doctor is not there. The Doctor claims he can destroy her with six simple words, and after she walks off he asks her aide "Don't you think she looks tired?".That evening, as snow (which is actually the ash from the destroyed ship) falls on London, the Doctor selects his new outfit from the TARDIS wardrobe, and joins Rose, Jackie, and Mickey for Christmas dinner. They watch Harriet Jones on the television, fending off rumours about her ill-health and a pending vote of no confidence in the House of Commons. The Doctor and Rose then get ready to set off again for more travels across space and time.