Rose Tyler, a young woman working in a London department store named Henriks, finds herself, one night after closing, surrounded by plastic mannequins that have come to life in the basement. She is saved by a man, introducing himself as "The Doctor", who tells her to flee the building and then destroys the transmitter that is being used to control the mannequins. As the upper floors of the store explode behind her, Rose rushes to the council flat that she shares with her mother, Jackie, clutching a mannequin arm that The Doctor pulled off during their escape. The next day, the Doctor follows a signal to Rose's home, and when the plastic arm comes to life, he subdues it with his sonic screwdriver. The Doctor then heads for his old blue police box, with Rose following him trying to get some answers. He just tells her to forget him and return home. When Rose looks back, the police box has gone.
Rose talks with her boyfriend, Mickey Smith, about her experience, and they find a conspiracy theory website that claims a man fitting the Doctor's description has had appeared throughout history. Rose and Mickey visit Clive, the man who runs the website. While Clive shows Rose various pieces of evidence to back up his idea that the Doctor is an immortal alien, Mickey notices a plastic rubbish bin that seems to be alive. He is pulled into it. Rose leaves Clive's house, and dismisses his claims to Mickey, not realising her boyfriend has been replaced with a plastic replicant. They head to a restaurant, where the fake Mickey presses Rose for information about the Doctor. As she starts to become suspicious, the Doctor appears and wrestles with the fake Mickey, dislodging its head in the process. The Doctor grabs Rose and takes her to the police box, which is revealed to be his TARDIS, and uses the fake Mickey head to lock onto a signal and materialize the TARDIS nearby. The Doctor explains to the shocked Rose that the fake Mickey was an Auton, controlled by the Nestene Consciousness, and that if he cannot stop it using a vial of "anti-plastic" liquid, it will destroy all humans on Earth. Leaving the TARDIS on the banks of the Thames, Rose identifies the London Eye ferris wheel as a possible transmitter, and she and the Doctor race towards it.
In an underground complex under the Eye, the Nestene Consciousness has taken residence in a large vat; the real Mickey is in a state of shock on one of the catwalks. While Rose sees to Mickey, the Doctor tries to negotiate with the Nestene Consciousness, held back by two autons. However, the Nestene has discovered the Doctor's TARDIS, and recognizing what he is and that he cannot make up for the destruction of its home during "the war", the Nestene activates all the autons at the Queens Arcade. Several shoppers are shot dead, including Clive after realizing what he knew was the truth, while Jackie manages to escape the Arcade, but ends up surrounded by autons. Rose uses a nearby chain to swing over to the Doctor and knock one of the autons holding him away, allowing him to defeat his other and dropping the "anti-plastic" vial into the Nestene. The Nestene wails in pain and explodes while the Doctor, Rose, and Mickey escape safely in the TARDIS. Jackie and the remaining shoppers find themselves safe as the autons stop functioning. After the TARDIS rematerializes safely, Mickey flees in a state of panic, while the Doctor offers Rose more adventures with him. Though Rose initially refuses as she is concerned about her mother and Mickey, she quickly joins with the Doctor when he explains that the TARDIS can also travel in time as well as space.
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