Fear Her

The TARDIS materialises on Dame Kelly Holmes Close on the day of the opening ceremony of the 2012 Olympic Games. The neighbourhood is preparing for the passing of the Olympic torchbearer, but the mood has been destroyed by the inexplicable disappearances of several local children. A council worker, Kel, also mentions that cars have been breaking down momentarily all day. The Doctor and Rose investigate and realise that the source of the problems is a solitary 12-year old girl, Chloe Webber, who is able to cause people to disappear by drawing them. The Doctor hypnotises Chloe and finds that she is possessed by an immature Isolus, an alien life-form used to traveling through space with a family of billions and which has crashed its pod to Earth due to a solar flare. The Isolus has befriended Chloe as she had a troubled childhood and it relates to her loneliness. Besides snatching people, this has also caused Chloe to draw a life-sized, exaggerated figure of her late violate father, which briefly has become animated.
The Doctor explains that if they can find the Isolus pod and provide it power, the alien will leave Chloe. A frantic Chloe draws the Doctor into one of her paintings, forcing Rose to try to find the pod herself. She rationalizes that the pod is located on the spot on the street where cars have been breaking down, and is able to dig it up with the council worker's help. With Chloe having already caused the entire crowd at the Olympic stadium to disappear and now intent on making everyone in the world disappear, Rose tries to find out how to power the pod. Thanks to visual indications from the Doctor's "picture", Rose understands that she needs to offer the pod heat mixed with emotional strength, which she does by throwing the pod towards the Olympic Torch. As the missing children start to reappear, Rose realises that so will the demon-like drawing that Chloe had made of her father. Rose and Chloe's mother are able, though, to calm Chloe enough and the - unseen - monster disappears.
As the torch-bearer approaches the Olympic Stadium, he staggers, but the Doctor completes the run and lights the Olympic Flame, allowing the Isolus to peacefully leave Chloe's body and return home. As the Doctor and Rose walk off to watch the Games, Rose remarks that however hard they attempt, nothing will ever split the two of them up. However, the Doctor becomes uneasy and surmises that a storm is approaching.

Love & Monsters

"Love & Monsters" is presented as an excerpt from the video diary of Elton Pope, a young ELO fan, describing his encounters with The Doctor. Elton's on-camera narration forms a present-day frame story to a series of flashbacks related to his investigation of the Doctor. Elton recounts a chance meeting with the Doctor, and recalls having seen the same man as a young child. Searching the Internet, he discovers others, including Ursula Blake, who have also reported similar experiences with the Doctor. Elton and Ursula form LINDA—"London Investigation 'N' Detective Agency"—with three others, Bridget, Bliss, and Mr. Skinner, and meet in a library basement to discuss their experiences, but soon their activities become more social in nature. Elton and Ursula become closer through these meetings.
One day, LINDA finds its meeting interrupted by the portly Victor Kennedy, who points out that LINDA has lost its cause and reinvigorates the group to seek out the Doctor's location. Elton is given the task of getting close to Jackie Tyler, Rose's mum. Elton manages to find Jackie but when he starts asking too many questions about Rose, Jackie shoos him off. Meanwhile, two of LINDA's members, Bridget and Bliss, appear to have left the group, Victor explaining their absence as having decided to move on in their lives. After one meeting, Elton and Ursula depart, while Mr. Skinner remains at Victor's request. When Ursula realizes she had forgotten her phone, the two return, and discover that Victor is really a grotesque alien being (later named an "Abzorbaloff" by Elton), with the faces of the former LINDA members and others protruding from his body, still conscious of themselves. Elton is unable to stop the Abzorbaloff from absorbing Ursula, but makes for his own escape.
As the Abzorbaloff chases him, Elton is forced down a dead-end alley. However, moments before the Abzorbaloff can touch him, the TARDIS appears and the Doctor and Rose step out; Rose angrily confronts Elton for upsetting her mom. The Abzorbaloff, now with the Doctor in range, tries to absorb the Time Lord, but the absorbed members of LINDA use their willpower to hold back the Abzorbaloff's body, forcing it to drop its cane. The Doctor realizes that the cane contains a field generator that keeps the Abzorbaloff in control of its body, and Elton smashes the cane apart. The Abzorbaloff and the absorbed people begin to dissolve, and while the Doctor realizes it is too late to save the others, he manages to use his sonic screwdriver to keep Ursula's essence alive in a piece of cement tile, which Elton has kept in his room. The Doctor realizes that he has seen Elton before as a young child, and apologizes to him for the death of his mother at the hands of an elemental shade he had been chases years ago.
In the conclusion of Elton's narrative, he demonstrates that he and Ursula still have a romantic, if not unconventional, relationship. He further postulates that while one could have a conventional life, "the real world is much stranger than that; it is so much darker, madder, and so much better."

The Satan Pit

While the Doctor and archelogist Ida investigate the strange door deep in the planet Krop Tor, Rose and the rest of the human crew flee from the advancing Ood, all possessed by The Beast and regroup to come up with a plan. The group initially believe Toby to be possessed by The Beast, but when they observe a force leaving his body and return to the Ood, they conclude that he has regained his own will. The Doctor makes contact with the crew, revealing that while the door had opened, nothing came out of it. He offers to rappel down the sides to explore further.
As the crew struggles to fight against the advancing horde, attempting to free Captain Zack who is trapped inside the control room and making their way to an escape rocket, the Doctor descends into the open door into a seemingly bottomless pit. The Beast communicates with the Doctor and the rest of the crew through the Ood; the Beast explains he is the epitome of evil across many different religions, as he had been sealed in the planet's Pit since the creation of the universe by the Disciples of the Light, and is seeking to escape. When the Doctor runs out of rope, he opts to drop down, causing Rose to be distressed over his fate. Ida finds herself unable to return to the surface and running short on air. As the Ood continue their attack, the crew is whittled down to just Zack, Rose, Danny and Toby, who board and launch the escape rocket.
The Doctor finds himself in a cave depicting the capture of The Beast, and discovers two jars on pedestals a few feet from each other. Touching them causes the cavern to fill with light, revealing the giant physical form of The Beast, complete with caprine head and humanoid body, chained to the walls of the cavern. The Doctor quickly deduces from the unintelligible grunts coming from The Beast that the consciousness of The Beast has already managed to escape. He also comes to understand that Krop Tor was a perfect prison for The Beast, as should he escape, the gravity field keeping the planet in orbit about the black hole would collapse, taking The Beast with it. The Doctor, aware that Rose will be put in danger by destroying the gravity field, proceeds to smash the jars, destroying the generators and causing the planet to fall into the event horizon, The Beast's physical form writhing in pain. The Doctor, though willing to sacrifice himself, manages to come across his TARDIS in another part of the cavern.Meanwhile, the escape rocket struggles against the black hole's gravity with the energy source now destroyed. The Beast repossesses Toby, defiant from being killed. Rose takes a yellow-stripped Boltgun and shoots out the rocket's viewscreen and disengages Toby's harness, causing the possessed being to be sucked out into space and into the black hole. The cabin is shortly sealed by automatic shields, but the rocket is still lacks the power to escape the gravity well. They suddenly find their ride has smoothed out and are being moved far away from the black hole; the Doctor, over a communications channel, reveals that he and Ida are both safe, and that he is using the TARDIS to tow the rocket to safety. However, the Doctor reports he did not have time to go back and save the Ood, innocent victims of the Beast's possession. Once safe, the respective crews regroup and then depart to go their separate ways. As they return to Earth, Zack reads off the list of personnel that died, including the Ood.

The Impossible Planet

The TARDIS arrives inside a "Sanctuary Base" used for deep-space expeditions; as Doctor and Rose explore it, they discover strange alien writing that the TARDIS is unable to translate. After a slight misunderstanding when first meeting the Ood, a docile race of empathic servants who work on the station, the travelers meet the crew of the base, led by acting Captain Zachary Cross Flane. The crew, which includes Science Officer Ida Scott, Head of Security Mr Jefferson, and archaeologist Toby Zed, are on an expedition on an anomalous planet, named "Krop Tor", in orbit around a black hole. Zack explains that a gravity well exists around the planet, allowing them to safely enter or leave the event horizon of the black hole, and that it is generated by an immense energy force ten miles within it, which they are drilling towards to understand its power. As the Doctor and Rose are acquainting themselves with the crew, the base is struck by a planet-quake, causing the section of the base containing the TARDIS to fall into the planet, and the two become resigned to help out the crew.
As the drill nears its target, a malevolent presence begins to make itself known; the Ood's translation spheres reveal messages about the Beast awaking, while Toby is unknowingly possessed by the Beast and kills a crew member. When drilling is complete, the Doctor offers to go with Ida into the bowels of the planet. After travelling down the shaft, the Doctor and Ida find a large circular disk, inscribed with more undecipherable markings, which the Doctor believes is a door. As they watch, the door begins to open; simultaneously, the Beast repossesses Toby and the Ood. The possessed Toby warns Rose and the remaining crew that the planet is now falling towards the black hole, and that the Beast is free, while the Ood, now claiming to be the Legion of the Beast, begin to close in on them.