Rose Tyler’s alarm clock goes off at 7:30 am. After bidding goodbye to her mother, Jackie, Rose catches a bus to her workplace, a department store named Henrik’s. Apart from lunch with her boyfriend, Mickey, her workday consists mainly of waiting for her shift to end. Finally, closing time rolls around, but before she can leave, she’s tagged to take the employees’ lottery money down to Wilson, the electrical engineer who works in the store’s basement. Wilson doesn’t answer the door to his office, and Rose, hearing movement elsewhere in the basement, investigates only to find the shuffling sounds coming from a room full of display mannequins. As Rose enters the room, searching for Wilson, the door slams shut behind her -- and the mannequins begin to move in, surrounding her. Just as they’re about to strike her down, however, a stranger grabs her by the hand and pulls her to safety.

Pursued by the mannequins, Rose and the stranger make their way to a lift. One of the mannequins reaches in after them, blocking the doors, but the stranger yanks its arm off and tosses it to Rose as the doors slam shut. Realising that the arm she’s holding is indeed solid plastic, Rose tries to convince herself that the “mannequins” were students pulling a prank, reasoning that only students would have the time and inclination to set up such a stunt. The stranger compliments her on her reasoning skills, but tells her that they weren’t students -- and when she mentions Wilson, the stranger informs her that he’s dead. The lift then arrives back in the store, and the stranger uses a small humming tube to fuse its controls, telling Rose that the mannequins are in fact living plastic entities controlled from a relay on the roof, which he now intends to blow up. He ushers Rose firmly outside, warning her not to tell anyone about what she’s seen; if she does, they’ll probably end up dead. Finally, he introduces himself as “the Doctor,” and slams the door shut. Shaken, Rose stumbles away from the store -- and just as she gets clear, a colossal explosion takes out the roof and top storey. Chaos erupts in the street as Rose turns and runs, right past a squat blue 1950s police box sitting in a nearby alley.

The explosion makes the nightly television news; all of central London has been closed off while police investigate. As Rose recovers from the shock at home, Jackie insists that she seek compensation for her traumatic experience, and advises her to sell her story to the papers. Mickey arrives, showing concern for his girlfriend and insisting that she join him at the pub for a stiff drink; however, Rose sees through him and realises that he actually wants to catch the last few minutes of the match on the pub’s TV. She assures Mickey that she’ll be all right, and urges him to go to the pub himself while she rests at home -- and, while he’s at it, to get rid of the mannequin arm, which she carried home with her while in a state of shock. Mickey picks up the disembodied arm and pretends that it’s choking him; Rose laughs politely. Mickey then heads off, tossing the arm into a nearby trash bin -- which continues to rattle long after he’s gone, as if something is moving inside...

The next day, Rose wakes at 7:30 again, but doesn’t need to rush off to work, since it doesn’t exist any more. As her mother again presses her to file a claim for compensation, Rose hears a rattling at the cat flap; at first she assumes that her mother has failed to nail it shut, but when she takes a closer look she sees that the nails have been pried loose. The flap then rattles again, and when Rose pokes it open, she sees the Doctor looking in at her. He’s just as surprised to see her, but when he raps on her head and confirms that she’s not made of plastic, he concludes that his tracker led him to the wrong place. Before he can leave, Rose drags him into her flat to answer a few questions, telling her mother that he’s part of the inquiry into the explosion. Jackie makes a not very subtle pass at him, and is irritated when he shows absolutely no interest in her.

While Rose prepares coffee, the Doctor explores her sitting room, flips through a teen magazine and speed-reads a copy of The Lovely Bones, and examines his own ears doubtfully in a mirror. He then hears a scuttling sound behind the sofa, and when he investigates, the mannequin arm leaps up and catches him by the throat. Rose enters with the coffee, asking what they’re going to tell the police, and although she sees the Doctor struggling to remove the arm from his throat, she assumes he’s pulling the same gag that Mickey did. She learns that this isn’t the case when the Doctor manages to pry it free and fling it away -- and it changes direction in mid-air, latching onto Rose’s face. Jackie, blow-drying her hair in the other room, doesn’t hear the sounds of the struggle as the Doctor tries to pull the plastic arm away from Rose; he eventually succeeds, using the same tube with which he fused the lift to deactivate the wriggling arm.

The Doctor then leaves, taking the arm with him, but Rose follows him, demanding answers and threatening to go to the police. He calls her bluff, and she changes her tack, asking his name; however, he insists that he’s just “the Doctor.” The plastic creatures aren’t after her; they’re after him, and she just got in the way. He’s the only one fighting them, while the rest of the human race goes about their daily routine, unaware that a war is being fought under their noses. Surprised that Rose is actually taking an interest in what he’s saying, he explains that he cut off the signal that was controlling the plastic arm -- not a radio signal, but thought control. But the force that brought the mannequins is still out there, and it intends to destroy the human race. Unsure whether to believe him or not, Rose asks him who he really is, and this time, he tells her: he’s the one who can feel the world turning beneath their feet and rushing through space, and he knows just how fragile it all is. And it’s time that Rose went back to her ordinary life and forgot all about him. Rose reluctantly sets off back to her flat while the Doctor heads towards a blue box standing on the corner. Moments later, Rose hears a strange wheezing, groaning sound, and turns back to see that the blue box has vanished.

Unwilling to let this go, Rose visits Mickey and uses his computer to conduct an online search for information. After a few fruitless inquiries, she locates a website with a blurry photograph of the Doctor. Rose sets up a meeting with the webmaster, Clive, and Mickey reluctantly drives her to Clive’s home; however, he stays alert in the car outside, ready to rush to the rescue if Clive turns out to be a dangerous online lunatic. As it happens, Clive seems to be a friendly enough family man with a wife and young son who tolerate his bizarre hobby. However, as Mickey waits for Rose to return, one of the plastic garbage bins on the sidewalk unexpectedly begins shuffling towards his car. Puzzled, Mickey examines the bin, but finds it empty -- and when he tries to close the lid, he finds that the plastic has warped around his hands, trapping him. As Mickey tries to pull himself free, the bin begins to growl, and it flips its lid up, yanking Mickey inside. The lid snaps shut, and a moment later, the bin belches loudly.

Meanwhile, Rose has accompanied Clive out to his garden shed, where he keeps a collection of clippings documenting the Doctor’s appearances throughout history. The man Rose recognised as the Doctor shows up in the crowd at the Kennedy assassination, in a photograph with a family who mysteriously cancelled their cruise on the Titanic at the last moment, and even in a drawing that washed up on the shores of Sumatra following the eruption of Krakatoa. There are legends of the Doctor woven throughout history, and his arrival always spells disaster and death for those unfortunate enough to encounter him. Unnerved, Rose asks Clive what he believes, and Clive tells her that he believes the Doctor is an immortal alien from outer space. Rose’s suspension of disbelief snaps, and she returns to the car, telling Mickey that Clive was a complete nut after all. In her disappointment, however, she fails to notice the fixed smile on Mickey’s face or the strange plastic sheen to his skin and hair...

Later, Rose and Mickey have settled down in a quiet restaurant, where Rose is trying to decide what to do for a job now that Henrik’s has blown up. However, Mickey seems more interested in discussing the Doctor, where Rose met him, and what he’s really up to. As Rose tries to change the subject, the Doctor himself shows up with a bottle of champagne and fires its cork directly into Mickey’s forehead -- revealing that Mickey is in fact a plastic replica. The replica’s hands transform into bludgeons and it attacks the Doctor, who grabs it in a choke hold and pulls its head off. This only slows it down a little. Rose triggers a nearby fire alarm, and as the restaurant’s terrified patrons flee, she and the Doctor run out the back, pursued by the now-headless replica. The Doctor fuses the back door shut with his all-purpose humming tube, the sonic screwdriver, and pops into his blue box, which is now located in the back alley. Since the gate to the street has been locked up, Rose has little choice but to follow the Doctor into the box. She promptly bolts straight back out again in disbelief, but as the replica begins to hammer down the restaurant door, she has little choice but to step back inside. This time, she stays inside, staring, while the Doctor closes the doors and the sight of the interior sinks in. The inside of the box is a gigantic control room with a glowing central console, and it’s much, much larger than the outside...

The Doctor wires the replica’s head to the console, explaining that, as it’s much more complex than the arm he took earlier, this time he should be able to trace the alien control signal to its source. He then turns to face Rose and calmly answers her questions about his ship; it’s called the TARDIS, short for Time And Relative Dimension In Space, and yes, the Doctor is an alien. As the shock sinks in, Rose realises that the real Mickey must be dead -- and from the Doctor’s nonplussed reaction, she realises that this genuinely hadn’t occurred to him. However, he does react badly when Rose notices that the replica’s head is melting; the control signal has been cut off, and the Doctor loses track of it before he can trace it to its source. Frustrated, he emerges from the TARDIS, and when Rose follows him, she finds that they are no longer in the back alley of the restaurant; the box has dematerialised from there and rematerialised on the bank of the Thames.

The Doctor tells Rose that the rest of the replica will have melted along with the head, but as she tries to deal with what’s happening, she realises that the Doctor has forgotten about Mickey’s death again. He insists that he’s got bigger things to worry about; the alien Nestene Consciousness is preparing to invade the Earth. Its protein planets were destroyed in the war, but the Earth’s atmosphere is rich in the toxins it needs to survive. The Doctor has a tube of “anti-plastic” with which to destroy it, but first he needs to find it. All he knows is that it must be using a transmitter of some kind, something like a gigantic dish or wheel -- something exactly like the London Eye, in fact, although it takes Rose several tries to point out to the Doctor that the thing he’s describing is located straight across the river. She and the Doctor rush across the bridge to the Eye, and Rose -- who’s actually beginning to enjoy herself -- locates an entrance to the service tunnels beneath the tourist attraction.

The Doctor and Rose descend into the pit beneath the Eye, where they see a gigantic vat of seething, glowing plastic -- the corporeal mass of the Nestene Consciousness. The Doctor requests permission to parlay as per Convention 15 of the Shadow Proclamations, and as he approaches the hostile alien entity, Rose finds the real Mickey huddled on a catwalk, terrified. She’s irritated to learn that the Doctor always knew that Mickey had probably been kept alive to maintain his replica, and that it never occurred to him to mention it; however, the Doctor brushes her off and addresses the Nestene on behalf of humanity, a young race with the potential to become something great. As he speaks, however, two mannequins walk up and grab him before Rose can shout out a warning. One of the mannequins searches the Doctor and finds the tube of anti-plastic, and the Nestene then reveals the TARDIS, which it has brought down from the surface -- and which it recognises as the product of a higher technology. The Doctor desperately tries to convince it that it’s misinterpreting the situation; he only brought the anti-plastic as an insurance policy, and he insists that he did his best to save the Nestene’s planets during the war. However, the Nestene has identified the Doctor as a Time Lord, and, believing itself to be under attack, it brings forward the invasion schedule, transmitting the activation pulse through the London Eye.

Rose desperately calls her mother on her cell phone, but the signal is breaking up, and Jackie doesn’t get her daughter’s full message. She’s gone into town to pick up a document on workers’ compensation from the police, and this done, she pops into the Queens Arcade shopping centre before going home. Clive and his family are also at the shopping centre, and they’re amongst the first to see the window dummies throughout the centre twisting and jerking to life. Clive watches in astonishment as the dummies smash their way out of their display cabinet, amazed to learn that everything he’d heard and written about was true. Unfortunately, he’s learned it the hard way, as one of the dummies’ hands hinges away to reveal a built-in gun that shoots Clive in the head. All hell breaks loose in the shopping centre as the mannequins open fire, and Clive’s screaming wife and son flee for the exits, as does the terrified Jackie. However, outside is no safer; dummies are walking the streets, gunning down fleeing pedestrians and vehicles. As Jackie huddles behind a crashed car, three dummies in bridal outfits smash their way out of a window behind her and bear down on her...

The force of the activation signal has brought down the ceiling in the pit, cutting off Rose and Mickey’s escape route -- and the Doctor, now being manhandled towards the seething vat by a mannequin, has the only key to the TARDIS. As Mickey clings desperately to the TARDIS doors, Rose realises that she’s the only one who can save the day; she’s got no job, no future, and no A-levels, but she does have her school’s bronze award for under-7 gymnastics. The Nestene, concentrating on the Doctor, fails to notice Rose using a fire axe to hack a hanging chain free from the wall until it’s too late. Rose swings out over the pit, kicking out at the mannequin holding the tube of anti-plastic and knocking it into the vat. The tube shatters, and as the Doctor overpowers his captor and flips it into the vat, the Nestene shrieks in agony, cracks of light appearing on its surface. The Doctor and Rose bolt for the TARDIS, and they and Mickey dart inside and dematerialise as the Nestene’s lair explodes. With the death of the Nestene Consciousness, the attacking window dummies revert to lifeless plastic, moments before the bridal dummies can kill Jackie.

The TARDIS materialises in a back alley nearby, and as Mickey rushes out and huddles gibbering behind a pile of rubbish, Rose calls her mother once again but hangs up once she’s determined that her mother is still alive. The Doctor smugly confirms that the Nestene Consciousness has been defeated, but admits that it’s all due to Rose. It’s time for the Doctor to be on his way, but before he goes, he offers Rose the opportunity to travel with him and see the Universe. She is tempted, but as the whimpering Mickey clings to her, she reluctantly decides that she’d better stay behind to take care of him and her mother. Disappointed, the Doctor closes the door of the TARDIS, and Rose watches sadly as it dematerialises before her eyes. But as she helps Mickey to his feet and starts to walk back to her ordinary, unfulfilling life, the TARDIS reappears behind her and the Doctor pops his head back out. “Did I mention it also travels in Time?” Rose turns to Mickey, kisses him on the cheek, and thanks him, genuinely, for doing absolutely nothing to help her. She’s made her decision, and as Mickey stands, stunned, in the alleyway, Rose rushes to join the Doctor in the TARDIS for the trip of a lifetime.