Dalek

The TARDIS is drawn off course by a distress signal, and materialises in a bunker in Utah, 2012. The Doctor and Rose Tyler find that the bunker is a museum, full of alien artifacts. An alarm is immediately set off, and they are taken to see the owner of the Vault — Henry van Statten, a billionaire collector of alien artifacts. Impressed with the Doctor's extraterrestrial knowledge, he invites the Doctor to see the "Metaltron", a creature he claims is the last of its kind. The Doctor enters the "Cage", where the creature is held, and begins to speak to it, offering his help. The creature responds by snarling in fury at him. The Doctor realises in horror it is a Dalek. Initially terrified at its threats of extermination, the Doctor is delighted to discover the creature is damaged and helpless, and attempts to kill it to purge the Dalek race forever, before being stopped by van Statten's guards.
Meanwhile, Adam Mitchell is showing Rose around the base. Adam shows her the Dalek, being tortured by a technician to force it to speak. Sympathetically, Rose asks to be taken down to the Cage to help the Dalek. Rose then touches the Dalek casing, which immediately absorbs her DNA and background radiation (a radiation that is picked up in mass quantities from time travel, and is the Daleks' sole power source). It escapes from its cage and downloads the entire internet, realizing that it is the only Dalek left. In response, the area is evacuated, and guards focus fire upon it, to no effect; the Dalek swiftly exterminates the guards. The Dalek demands to speak to the Doctor, and tells him that it was able to regenerate its casing, but was unable to find any other Daleks or orders, and will follow the default function: the extermination of everything in its path.
As Rose and Adam are escaping from the Dalek, the Doctor tries to stall to save them. Adam escapes, but Rose is cornered by the Dalek and is seemingly exterminated. Horrified, the Doctor blames van Statten for everyone's deaths. However, the Dalek has not killed Rose, as her DNA is making it hesitant. It instead negotiates, trading her life for access past the bulkheads which are obstructing its way. The Dalek then travels to van Statten's office, and is about to kill him before Rose intervenes and offers the Dalek its wish: freedom.
On the highest level of the museum, the Dalek creates a hole and opens its casing to directly feel sunlight for the first time. The Doctor arrives, gun in hand, and orders Rose to move. Rose refuses; the Dalek is changing, as it could not kill her or van Statten. Appalled at his own actions, he lowers his weapon. Both he and the Dalek realise that the Dalek is mutating further, and is becoming unable to conform to the Dalek objective. It asks Rose to order its death, and after being given the order, annihilates itself.At the end of the episode, van Statten's assistant Diana Goddard orders van Statten's mind wiped and the vault filled with concrete. At the TARDIS, the Doctor ruefully observes that as the last survivor of the Time War, he "wins". He also tells Rose that he would be able to sense the presence of other Time Lords had they survived. Adam then comes by, telling the Doctor that Goddard is sealing the base. Rose invites Adam aboard the TARDIS, which he enters with a puzzled expression before it dematerialises.

World War Three

Following from the cliffhanger in "Aliens of London", the Doctor's extraterrestrial constitution allows him to survive the electrical pulse administered by the Slitheen Green, which has killed the other alien experts in the room. He manages to direct the charge to Asquith, and the shock spreads to Green and the other Slitheen via their communication devices. Margaret Blaine is temporarily stunned, allowing Harriet Jones and Rose Tyler to escape the room in 10 Downing Street where she had them cornered, while Mickey Smith is able to push aside the police inspector who was advancing on Jackie Tyler. The Doctor attempts to get the police, but by the time he has returned, the Slitheen have gotten back into their suits. Green instead pins the deaths of the alien experts on the Doctor, and orders him shot on sight. The Doctor escapes to the upper floors of 10 Downing Street, and reunites with Rose and Harriet in the Cabinet Rooms where they try and determine what Emergency Protocols are in place for an alien invasion. Before sealing off the rooms, the Doctor confronts the Slitheen and learns that they are a family rather than a race, and they are not invading Earth, but rather raiding it for some commercial purpose.
The Emergency Protocols are found to be of no help as they merely list the alien experts already dead in the room downstairs. They also reveal that the United Kingdom cannot launch nuclear weapons at the Slitheen as the codes can only be released after authorization by the United Nations. Gathering all the information they have found about the Slitheen, the Doctor deduces that they are a calcium-based lifeform from Raxacoricofallapatorius, and that they use compression collars to squeeze their bodies into the human skins, which accounts for their flatulence. Although the Slitheen have shut all communications to the Cabinet Rooms, Rose's tampered phone allows her to make contact with Mickey and Jackie, now safely in the former's flat. The Doctor gives Mickey instructions on how to log on his computer into the UNIT website, and uses that to determine that the Slitheen ship is presently in the North Sea, transmitting some signal that Mickey attempts to decode. However, as he works, the Slitheen posing as a police inspector breaks in, but thanks to advice from the Doctor, Jackie kills it by dousing it with copious amounts of vinegar.
Back at Downing Street, Green and the other Slitheen declare a matter of national security and request that the UN release the activation codes to strike against a fictitious mothership that is hanging over London. The Doctor realizes that the Slitheen actually plan to fire the weapons against other countries in order to start World War III so they can sell the Earth's radioactive remains as a fuel source, which they have already begun advertising through the signal Mickey has decoded. The Doctor tells Rose and Harriet that he knows a possible solution, but that it might cost their lives. Jackie, who had been pestering him for endangering Rose's life and is still on the phone, is outraged, but Rose and Harriet both tell him to go ahead, the latter even casting her timidity aside to order him as an elected representative. Complying, the Doctor helps Mickey to hack online into the controls of the Royal Navy HMS Taurean, a Trafalgar class submarine off the coast of Plymouth, and to fire a non-nuclear Harpoon missile at 10 Downing Street, where all the Slitheen conspirators are now gathered. The area around 10 Downing is cleared while the Doctor, Rose, and Harriet take shelter in a cupboard. The Slitheen's last second attempt to escape is delayed by the difficulty of putting on their human suits and they are caught in the explosion when the missile hits. The Doctor, Rose and Harriet all survive, and Harriet takes charge of the scene with a new found authority. The Doctor - who had found her name familiar when he first met her - suddenly remembers that she is due to become a highly successful Prime Minister and "the architect of Britain's Golden Age". The entire event is dismissed in the press as a hoax, and the Doctor has Mickey use a special computer virus to wipe all records of his existence from the Internet.Jackie is now impressed by the Doctor and wants to invite him for dinner to get to know him better, but he declines fiercely. Instead, he separately invites Rose and Mickey - who has now earned his respect - to go travelling some more immediately. Mickey, still overwhelmed by the Doctor's adventurous lifestyle, declines but Rose packs some belongings and boards the Tardis.

Aliens of London

The Doctor returns Rose back to Earth in the TARDIS, but miscalculates, ending up 12 months after he first left with Rose instead of 12 hours. As such, Jackie, Rose's mum, is furious with the Doctor, and Rose's boyfriend, Mickey is upset as he was suspected of murdering Rose. While Rose expresses her frustration to the Doctor of not being able to tell the truth of where she's been, they witness a spacecraft crash through Big Ben and fall in to the River Thames. Central London is shut down while its population become excited at the possibly of first contact with an alien species. The Doctor suspects trickery, and uses the TARDIS to land where the alien craft and its pilot has been taken. Along with Dr. Sato, he discovers that the alien craft was launched from Earth, and its pilot was nothing more than a Earth pig, modified by alien technology.
Meanwhile, the government is unable to locate the British Prime Minister due to the confusion of the crash, and MP Joseph Green is named acting Prime Minister at 10 Downing Street. However, Green is revealed to be a Slitheen, a calcium-based alien species that compress their bodies into large human "suits" resulting in frequent releases of flatulence, along with two other high members of the government, Margaret Blaine of MI5 and Oliver Charles, an MP for the Department of Transport. While they secretly celebrate successfully luring the humans into their plan, they are unaware of their conversation being witnessed by Harriet Jones, a backbench MP.When the Doctor returns to Rose, they are surrounded by soldiers, prompted by a call from Jackie to an Emergency Alien Hotline, and escorted to 10 Downing Street. The Doctor is asked to join a panel of alien experts, including those from UNIT, while Rose is escorted in the building by Harriet. Harriet explains the aliens to Rose, and together discover the corpse of the Prime Minister. They make to reveal their discovery but are caught by Blaine, who begins to unzip her human suit to attack them. Meanwhile, as the Doctor attempts to convince the experts of the forgery of the events, another human-disguised Slitheen sends an electrical shock through the assembled group, including the Doctor. These events lead to a cliffhanger, resolved in "World War Three"

The Unquiet Dead

The Doctor attempts to pilot the TARDIS to Naples in 1860 to show Rose the past, but misses short, ending up in Cardiff in 1869. While they land and Rose changes into more appropriate garb, there is trouble in a nearby funeral parlour run by Gabriel Sneed and his servant girl Gwyneth - the corpse of a grandmother has been taken over by a blue vapour, killing her mourning grandson Redpath, and then escapes the parlour. Gwyneth with her clairvoyance senses that the corpse, per her last desire, is going to see Charles Dickens at a nearby music hall. In the middle of his performance, the blue vapour leaves the woman, scaring the audience away and attracting the attention of the Doctor and Rose. Gabriel and Gwyneth arrive to retake the corpse as the blue vapour disappears into the pipes, and they are also forced to kidnap Rose by knocking her out with chloroform when she confronts them. Charles accuses the Doctor of ruining his performance, but after the Doctor gushes over his literary genius, and learning that an adventure is afoot, Charles gladly joins up to help.
At the funeral parlour, Rose wakes up and is borne down by the animated corpses of Redpath and his grandmother. The Doctor and Charles arrive, breaking into the parlour and rescuing Rose; the Doctor attempts to learn from the corpses why they are doing this, and determines that the parlour is built on a rift in spacetime, and the blue vapours are beings crossing through the Rift; they are able to use the corpses for a short time, but cannot sustain them. Rose talks more with Gwyneth, and her clairvoyance is discovered, an effect of living in the parlour since her parents died, according to the Doctor. Using Gwyneth as a channel, they hold a séance to directly communicate with the beings, who they learn are called "Gelth", their bodies destroyed as part of the Time War. The Doctor offers the Gelth temporary use of corpses only until he can transport them to a place where they can build new bodies, using Gwyneth as a bridge to cross the Rift.
As the process starts, the number of Gelth is much higher than anticipated, and their true motive is revealed: they are willing to kill the living to give themselves more hosts and take over the planet. Gabriel's neck is broken and his body taken over by a Gelth as Charles flees the parlour, leaving Rose and the Doctor trapped. Outside, Charles notes that the beings are affected by gas, and returns to the house, extinguishing the gaslights and turning the gas on full. The Gelth are forced to abandon the corpses and though the Doctor tries to encourage Gwyneth to send them back across the Rift, she cannot, nor can she leave; instead, she takes out a box of matches, intending to ignite the gas and killing the Gelth along with herself. The Doctor, Rose, and Charles flee the parlour before it is engulfed in flames. As the Doctor and Rose head back to the TARDIS, Charles thanks them for their help and makes a commitment to patch up things with his family and finish The Mystery of Edwin Drood, though the Doctor notes later to Rose that Charles will die within the year, leaving that work unfinished, but they have made him feel more alive than he ever has been. The Doctor and Rose give their goodbyes and disappear in the TARDIS. An astounded and delighted Dickens walks away through the streets of Cardiff, greeting everyone he passes and quoting from his book A Christmas Carol; "God bless us, everyone!"

The End of The World

The Doctor takes Rose to five billion years into her future in the TARDIS, landing on "Platform One", a space station in orbit around Earth; the earth has long since been abandoned and under the National Trust, but as money has run out, it is about to be destroyed by the expansion of the Sun, only presently held back by gravity satellites. The Doctor uses "psychic paper" to pass as their invitation to the party, and he and Rose find many elite extraterrestrial beings there to celebrate the end of the earth in the protection of Platform One's automated shields. The guests include Lady Cassandra O'Brien Dot Delta Seventeen, simply a face on a large piece of skin that must be continually moisturized, mounted on a frame with her brain in a jar below it, who calls herself the last human in the universe. The guests exchange gifts as part of the celebration (including Lady Cassandra's gift of a Wurlitzer jukebox, calling it an "iPod"). Rose is overwhelmed by the strange beings and customs as well as how distant she is from home, and leaves to an observation room to collect her thoughts. The Doctor follows her, and tries to cheer her up by allowing her to call her mum Jackie after altering her mobile phone to be able to work over the distance in time; this however only serves to depress Rose more.
Meanwhile, the gifts brought by the Adherents of the Repeated Meme, small metallic spheres, are revealed to contain robotic spiders that immediately work at disabling functions on Platform One. The Steward of Platform One recognizes something is wrong, but is killed when the spiders cause the solar filter of his room to lower, exposing him directly to the powerful solar radiation. The Doctor goes to investigate with the help of Jabe, a humanoid plant being from the Forest of Cheem, and discover the Steward's death and the spiders. Rose attempts to learn more from Lady Cassandra but only gets more upset over Cassandra's arrogance, and walks away, only to be knocked out by members of the Meme. She wakes up in an observation room, the solar shield slowly lowering, and calls for the Doctor to save her. The Doctor finds he can stop and raise the shield, but cannot unlock the observation room, and so turns to the various guests.
The Doctor uses a spider that he captured to determine that while the Meme released them, they are only empty shells, and that the real controller is Lady Cassandra. Cassandra admits to this, and was planning to use the situation as a hostage crisis to get money to pay for her repeated operations, but now will simply let the assembled guests die, then profit from the stock increases of their competitors when they are dead. Cassandra transmats to her ship as the spiders bring down the shielding and the gravity satellites are turned off ; The direct radiation causes the solar filters to strain and crack, killing several of the guests from the intense radiation exposure, and leaving Rose to scurry to find some shelter within the observation room. The Doctor and Jabe travel to the bowels of Platform One where the system to restore the automated shields is located, though it requires one of them to travel through several spinning fans. Jabe recognizes the Doctor as the last Time Lord after The Time War, and sacrifices herself to hold down a switch to stop the fan blades, allowing the Doctor to reactivate the system just before the expanding Sun hits the station and destroys Earth.The Doctor returns to the remaining guests and Rose, free of the observation room, and uses a device to transmat Cassandra back onto the station. In the elevated temperature and without moisturizing, Cassandra begins to dry out and crack, and while she begs for mercy from the Doctor, he refuses to listen, and shortly, Cassandra explodes. Rose notes that with all the events that occurred, no one had witnessed the actual destruction of Earth. Returning to Rose's present, the Doctor explains to her that his own planet, Gallifrey, was destroyed in the wake of a great war and that he is the last Time Lord, and that people tend to forget that things don't last forever. Rose sympathizes with the Doctor as they enjoy some chips on a sunny London afternoon.