Elton Pope is running across a field on Earth, and comes to a series of buildings. He spots the TARDIS and reaches out to touch it, and then hears Rose yelling from inside. Elton runs to investigate and hears the Doctor and Rose yelling. He continues inside and comes face-to-face with an alien humanoid. The Doctor distracts it with a pork chop long enough for Rose to run in with a bucket and hit the alien with the contents. It's the wrong bucket, and a chase ensues. Rose eventually gets the right bucket, and the Doctor spots Elton and seems to recognize him. Terrified, Elton runs off. Outside, he hears the TARDIS depart.
Elton is making a video log and explains that the incident he just described isn't the first time he has met the Doctor. He warns the audience that it will get scary, but first introduces his camera operator and good friend, Ursula Blake. They go to his home and Elton talks about how he was three years old, he found the Doctor in his kitchen in the middle of the night. He doesn't know why the Doctor was there. Elton explains that he works as a transport manager and has a normal life. Two years ago, the Autons went on a rampage in the middle of London. he survived, but a year later, he witnesses a spaceship crash through Big Ben. Then, on Christmas Day, his windows were blasted inward by a vast spaceship passing overhead. After that, the Doctor met Ursula Blake, Victor Kennedy, Jackie Tyler, and the Doctor... and realized the truth.
Elton checked the Internet and eventually found Ursula's web site, which had a photo of the Doctor. He meets her and she explains that she took the photo during Christmas Day. She didn't realize how significant the Doctor was until Skinner contacted her. Skinner has put together an inner sanctum of people studying the Doctor. Elton explains that he met the Doctor as a child, and he hasn't changed in all those years. Ursula introduces Elton to the rest of her group: Mr. Skinner, Bridget, and Bliss. Each of them has their own theories about the Doctor and what he represents. They create a name for the group, LINDA, and meet each week. Soon they were having potlucks and readings, and bonded as friends, and even created a band.
One Tuesday night in March, a man came to see the group: Victor Kennedy. He refuses to shake hands and explains that he suffers from a skin condition. Kennedy explains that he's there salvation, and shows them video of the Doctor and Rose. The Doctor recognizes it and explains he heard it when he was 3, and it woke him up and he went downstairs. Kennedy then gives them stolen Torchwood files and delegates tasks to each of them. In a week they'll regather and coordinate their data, and come one step closer to capturing the Doctor. As the others go, Kennedy asks for a word with Bliss in private. The others leave, failing to hear Bliss' scream.
Kennedy rigorously trains the group to find the Doctor. When Elton asks about Bliss, Kennedy claims that she left a message saying that she's getting married. They discover a recent spotting and Elton goes to the field and spots the TARDIS, the Doctor, Rose, and the alien. When he returns and reports failure, Kennedy is furious and Ursula comes to Elton's defense. Their sponsor then suggests they try to find Rose, and explains the Torchwood files on Rose were corrupted by a Bad Wolf virus.
The members spread out to search London, and Elton quickly finds a woman who directs him to Jackie as she goes to the laundromat. He quickly gets himself invited into her home and she flirts with him. Elton notices the photos of Rose, and Jackie explains that she goes traveling, but is vague about the details. Elton reports back to the group, and even Kennedy is impressed. He tells them to come up with a full plan of attack and tells Elton to do anything to get the information. As the others go, Kennedy asks for a word in private with Bridget. Mr Skinner gives her a friendly kiss before he leaves. Outside, Ursula comments on the kiss and he admits that he has hopes for the future.
Jackie keeps finding things for Elton to come over and repair, and she continues to flirt with him and offer him wine. She finally tells him that they have the place to themselves and then spills wine on his shirt. Jackie insists on him removing it to wash, and Elton goes to the bathroom to prepare. When he emerges, he hears Jackie talking to Rose on the phone. She sees Elton and admits she was being stupid because she's lonely. Jackie asks him to go, and Elton says he's going to go a pizza and spend time with her as proper mates. Jackie agrees, and Elton goes out for pizza while realizing there is someone for him: Ursula. However, when he gets back, he discovers that Elton has a photo of Rose and the TARDIS in his jacket. She warns him that she'll do anything to protect her daughter and the Doctor, and tells him to leave despite his protests.
Elton returns to the remaining members of LINDA and insists that what they're doing is shameful. Kennedy is furious that he broke cover, but Elton insists that the group has gone wrong since he showed up. Elton leaves and invites Skinner and Elton to leave with him, and invites Ursula out for dinner. She accepts, and Kennedy warns that Elton will never know what the Doctor was doing in his house. Elton accepts that and wishes Kennedy luck. As they go, Kennedy asks Skinner to stay for a minute, saying he has a number to track down Bridget. He agrees and Elton and Ursula wish him luck.
Outside, Ursula realizes that she left her phone. They go back and discover that Skinner is nowhere to be seen. Kennedy, holding a paper up in front of him, tells him that Skinner has gone to the toilet. When they point out they don't have a toilet, they hear Skinner cry for help. Kennedy's hands are inhuman claws, and he removes the paper to reveal that he is an alien. The faces of Bridget, Bliss, Skinner, and others are protruding from his skin, still able to speak and see. "Kennedy" explains that he is an Abzorbaloff, and he absorbed them all. It plans to absorb the Doctor and all of his knowledge. To do so, he'll absorb Jackie.
Ursula grabs the alien's cane and threatens to hit him, but the Abzorbaloff grabs her and absorbs her into his body. She warns Elton not to touch her, and admits that she's sorry he can't touch her. Elton begs Kennedy to release her, but the Abzorbaloff explains that the process is irreversible. Ursula reads his thoughts and warns Elton that he's next. The others agree and Elton runs out the door and Kennedy chases him down the street. Elton comes to a dead end, and admits that everything he ever wanted has been absorbed. The Abzorbaloff invites him to join them and reaches out, but the TARDIS appears behind him. Rose storms out, furious that Elton has upset Jackie. The Abzorbaloff is eager to capture the Doctor and explains from Clom, the twin planet of the Slitheen homeworld. He threatens to absorb Elton unless the Doctor surrenders himself, but the Doctor tells the Abzorbaloff to do what he wants. However, he tells the others to fight back. Ursula leads Bridget, Skinner, and Bliss in an effort to pull apart their captor. The Abzorbaloff drops its cane and Elton picks it up, revealing the power source within. The alien then melts into the concrete. The Doctor explains that the cane limited the Abzorbaloff's abilities, and without it, it's been absorbed into the earth. Ursula's face appears in one of the bricks in the pavement, and she says goodbye to Elton. As he cries, Rose goes over to comfort him.
Afterward, the Doctor explains that years ago, he detected a living shadow in Elton's house. He stopped it but wasn't in time to save Elton's mother.
Later, Elton is in his room and considers everything lost, all because he came into contact with the Doctor for only a few moments. He wonders if Rose and Jackie will pay a similar price. However, he still has Ursula. The Doctor was able to separate her from the Abzorbaloff's remains using his sonic screwdriver, although she's trapped in a piece of pavement. Elton insists that he loves her, and they still have a bit of a love life. Finally, he admits that no matter how much darker and madder the world is, it's still a better place.