On a busy London street medical student Martha Jones is on her way to work; but her day has not begun peacefully. Speaking to her sister Tish, brother Leo, mother Francine and father Clive in turn on her mobile phone, she finds herself in the midst of an argument concerning Leo’s upcoming 21st birthday party; the crux of the debate being the presence of her father’s new girlfriend at the event.
As she turns off her phone a tall man with a long brown coat steps out in front of her, taking off his tie.
And as quick as he arrived, he is gone. Martha looks after him in bemusement before continuing her way to the Royal Hope Hospital, where a leather-clad courier, his face concealed by a heavy helmet, walks into her and stalks off without a word. Soon after she dresses herself at her locker, drawing back as a bolt of static electricity launches from the door to her hand.
Some time later she is with the other medical students, doing the rounds with the somewhat austere Mr Stoker. After several failed diagnoses from his students he concludes that one of the patients, an elderly woman named Florence Finnegan, is suffering from a simple salt deficiency.
Moving through the foyer Martha notices the courier again, who is joined by an identical looking counterpart, both standing stiffly side-by-side as the group move on to the next patient, Mr John Smith.
Mr Stoker invites Martha to examine him and she realises that the man is the same one who approached her in the street earlier, and comments on his somewhat strange behaviour. He claims that is wasn’t him and she asks if he has brother, to which he replies “No, not anymore”. He goes on to explain that he has been in bed since the previous night.
Somewhat confused she goes on to examine his heart, but realises something is wrong when his pulse appears to beat in two separate places on his chest. Mr Stoker cynically notes her difficulty to locate a heartbeat and then points out that she has failed to examine the patient’s chart. He reaches for the clipboard, only for it to zap him with a static charge.
As the students complain of similar experiences Stoker puts it down to the build up of static electricity in the wake of a thunderstorm. He randomly asks his pupils who discovered such knowledge and Mr Smith, alias the Doctor, chimes in that it was Benjamin Franklin, one of his friends. Not amused, Mr Stoker leads the way out of the ward.
At lunchtime Martha is on the phone again, this time talking to her sister Tish, commenting on their father’s girlfriend Annalise. The only interruption is Mr Smith stalking the corridors in his dressing gown, as if looking for something. The conversation soon turns to the subject of weather, as Tish notices that a rain cloud has formed over the hospital. Moments later events take an even stranger turn as the raindrops begin to fly skywards, lifting from the windowpanes. In a flash of light the room in which Martha and her colleague Julia are standing begins to shake.
Blinding light pours from outside the window as the two women are thrown to the ground. Glasses smash and the contents of shelves are thrown to the ground, before the turbulence suddenly stops. Shocked, Martha gets to her feet and peers out of the window, realising that they are no longer in London. “We’re on the bloody moon.”
Sure enough the building stands on the lunar landscape, and as the patients gaze out of the windows in wonder the emotion overtakes them, and they begin breaking down in tears. Back on Earth Tish arrives at the site of the hospital, only to find a large crater in the ground where it once was. She tries to speak to Martha on her phone but there is no reply, all that remains is a tall blue Police Box standing on the opposite street.
In the hospital corridors panic has set in. Martha hurries to calm people but cannot help but marvel at the sight before her at the windows. Reaching forward to open one Julia warns her not to or the air will be sucked out. She retorts that the windows are not airtight in the first place; if the air were to be removed it would have already happened.
Mr Smith, now dressed in his suit, has overheard their conversation and compliments Martha on her reasoning, before asking her name and enquiring if there is a balcony nearby. She tells him of one and he asks if she wants to come with him outside. He warns her they could die but she comments that they might not. Again he seems impressed by her attitude, and together they walk off, leaving Julia alone.
Together they arrive at the doorway to the balcony and then step outside, where they realise that the air is still present. Suddenly events seem to overcome the young student as she thinks about the life she has just left behind on Earth. She manages to overcome her emotion and begins to marvel at the beauty before her.
She enquires what is going on and deduces herself that it must be extra-terrestrial activity, which matches with the strange goings on of the past few years. She recalls the battle of Canary Wharf, and explains that her cousin Adeola was one of those caught up in the crossfire. Her companion claims he was also involved in the battle and then falls quiet.
Martha promises him they will find a way out and he reveals to her that his name is not Mr Smith, he is known simply as the Doctor. Martha protests at the ease with which he uses the title she has been working hard for, but the Doctor is already working to find out how the air has been contained; and discovers by throwing a stone into the distance that a force field has been set up to contain the building; which leads Martha to realise that with the air contained, it will not last long.
She asks who has done this and as a rumbling appears from overhead the Doctor tells her that she can ask them herself. Sure enough three giant spaceships loom above them; giant cylindrical shapes painted in black, which roar into a land some distance away. Once settled the inhabitants of the ships begin to advance; armoured soldiers marching through the force field with militant ease. Martha marvels at the real-life aliens before her and the Doctor announces their name: the Judoon.
Mr Stoker observes from his window as they continue to advance but is interrupted by Florence when she enters his office, asking for help. He fobs her off, more worried about the current situation outside. She insists he can help her and into the office march the two couriers, flanking her on either side.
She explains that there are great tests to come, horrible deeds, some of them her own. Bemused he looks on as Florence insists that she must survive through all this, and to do that she needs blood. The couriers walk forward and grab him, as Florence continues to prepare herself, producing a drinking straw from her handbag. She advances on him and he screams in agony.
Meanwhile the Judoon force their way into the hospital, causing the patients to run for their lives. Assuming formation in the reception area one of them removes its helmet, revealing a giant rhino-like face beneath. It shouts orders in a strange language and the others raise their guns. The patients cower in fear as Morgenstern, another medical student, walks forward and greets them.
The leader points it’s gun at him but doesn’t appear to fire; instead it scans him and records what he says, before adopting an English dialect. It claims the man will be catalogued as a human and draws a cross on his hand. Soon the others are doing the same to the rest of the humans, as the Doctor and Martha watch from their hiding place on the balcony.
The Time Lord admires the small shop in the hospital foyer before explaining that the Judoon are intergalactic police-for-hire, who have brought the building to the Moon as neutral territory, the Earth being out of their jurisdiction. The rain and static were a result of the preparations for the transfer. He theorises that if they are cataloguing all humans, they must be looking for something extra terrestrial, which makes things much harder for him.
Martha laughs at his insinuation but continues to follow him as he moves away; the Judoon Commander meanwhile begins ordering his soldiers onto different floors of the hospital to search out the non-human entity. Morgenstern follows, telling the other humans not to panic. His words however go unheard as one of the captives tries to assault the creatures with a vase, only to be executed for his crime. “Justice is swift.”
Elsewhere, the Doctor is trying to hack into the hospital records with the Sonic Screwdriver, which Martha finds less than impressive. He finds that the software has been locked down, which gives him the opportunity to explain to Martha the reason he arrived in the hospital in the first place; to investigate the strange activity that had been building up for some time.
After Martha asks why the Judoon cannot be left alone to find the alien the Time Lord tells her that if the creatures find the building guilty of harbouring an alien being they will execute everyone inside, so he needs to find it first. Martha departs to try and warn Mr Stoker but when she arrives in his office all she finds are the two couriers, the lifeless body of her tutor and Florence, leaning over the body with a bloodstained straw protruding from her mouth.
Florence tells her servants to kill the girl and they follow her out, pursuing her as she rejoins the Doctor. Together they run through the hospital corridors, rushing toward an X-ray room where the Doctor uses the sonic screwdriver to increase the radioactivity by 5000%. Martha assists him it zapping the courier and he falls down dead.
Absorbing the radiation into his own body the Doctor is rejoined by Martha, and he starts to force the energy into his left shoe, which he rips off and throws into the bin, complaining of an itch. Astounded, Martha claims he is mad and, misinterpreting her, the Doctor removes his other show to avoid looking stupid.
He explains that the creature was a Slav, a servant of the creature the Judoon are looking for. As Martha explains about Mrs Finnegan the Doctor realises that his Sonic Screwdriver has been destroyed in the blast, but throws it away as Martha speaks in a more stern tone. He focuses on what she says and realises that the creature is an internal shape shifter, and was assimilating the blood rather than drinking it.
In a corridor elsewhere in the hospital, Florence wanders about as the other patients continue to panic. One of the Judoon approaches her and scans her, identifying her as human. The Doctor has realised this and rushes to warn the intergalactic storm troopers, stopping only to avoid the second Slav. Martha takes the opportunity to ask him if he has a partner, but he is not interested, more amazed at the human capacity to be more interested in personal information than the bigger picture.
They continue into the corridors, but the Judoon are waiting for them. They scan the Doctor and identify them as non-human, leaving Martha dumbstruck as he leads her off into another run. The Judoon fire after them unsuccessfully as they return to a different floor, one the creatures have already checked and therefore will most likely not do so again.
They then return to Mr Stoker’s office, where the pale lifeless body of the former Consultant awaits them. The Doctor identifies the work of a Plasmavore, presumably on the run. After Martha closes the dead man’s eyelids they leave, but the Judoon are already on their tail.
Spurred by the sight of an MRI lab sign, the Doctor tells Martha to stay behind and hold the advancing monsters off. He tells her that she could save a thousand lives then leans forward and kisses her. He dashes off, leaving her speechless.
Tearing down another corridor he arrives in the MRI scanning room, where Florence is busy tampering with the controls. The scanner itself crackles wildly and to distract her the Doctor begins to play the fool, talking to her about the monsters stalking the hospital. She ignores his muttering but he begins to annoy her and so she orders her Slav to hold him.
Meanwhile, the Judoon continue to search for the non-human and when they come across Martha they scan her, finding traces of a non-human nature inside her.
The Doctor asks Florence what she is doing and she claims she has increased the magnetic field to a degree of 50,000, enough to wipe out the brain stems of every living creature within 250,000 miles, including everything on the half of the Earth’s surface facing the moon, but at the same time leaving herself safe. Asking why she would do such a thing the Doctor is stunned by the Florence’s plan to use the empty Judoon ships to make an escape.
Again playing the fool the Time Lord manages to make her admit that she is the one the Judoon are looking for, but he lets slip that the creatures are increasing their scan, triggering her to realise her cover must be increased. She reaches for her handbag and pulls out her straw. The Doctor tries to make a joke but she comments that he laughs at the darkness on purpose, and he needs some peace. The Slav holds him tighter, exposing his neck and she stabs the straw into his flesh, before sucking his blood.
In the corridor Martha is scanned again but only a small contact with non-human life is detected. The Judoon move on after handing her a form with which to claim compensation.
As Florence continues to suck the Doctor’s blood his eyes grow heavy. Suddenly the doors fly open and the Judoon march in. The Slav drops the Doctor, prompting Florence to pretend the shock of the entrance has killed the young man in the room with her. They scan the lifeless body and detect that he is the non-human life form, but is now dead.
Martha realises what has happened and uses one of the Judoon devices to scan Florence, the Doctor’s blood now highlighting her as a non-human; a Plasmavore charged with the murder of the princess of Padravore Regency 9. Confessing to her crime she orders the Slav to stop her captors but they manage to destroy both her and her slave, however they are too late to prevent her from making the final connection of the MRI scanner.
The Judoon refuse to do anything; their jurisdiction has ended and they must now leave. Martha is left with the Doctor’s body in her arms as the Oxygen levels of the hospital begin to plummet and the armed soldiers return to their ships. Administering CPR on the Time Lord, Martha tries to revive him but to no avail. With her Oxygen failing she kisses him and suddenly he awakens. She weakly mutters that the scanner has been tampered with and so he staggers limply to his feet and moves over to the control panel.
As bolts of electricity zap across the hospital he struggles to disconnect the machine, relying on luck to lead him to the right choice of which connection to remove. It serves him well and soon the scanner is disconnected, but the oxygen levels are still falling.
Moments later he carries Martha in his arms, watching at the window as the Judoon ships depart. He urges them to reverse the transportation of the hospital and sure enough it begins to rain. In a flash of light the hospital returns to Earth, with paramedics ready and waiting to attend all those who have passed out.
Martha makes her way outside where Tish runs towards her, relieved to have her back. Martha however is more concerned with the whereabouts of the Doctor, who has made his way toward a large blue box on the opposite side of the street. He waves but after Martha looks away for one second he, and the box, are gone.
Later that night Martha sits alone in her room, a radio reporting an interview with Morgenstern, who claims that life on other planets is real, just as Mr Saxon has said. Martha stops to think about the unique events of the past few hours, but soon after she is once again mixed up in a family feud again; this time at Leo’s party. As her mother and Annalise take to the streets outside a pub in a fit of anger the others look on. Eventually the young blonde girl runs off, pursued by her lover, Martha’s father.
Soon the others are running off as well, leaving Martha seemingly alone. However as she looks around she notices the Doctor waiting for her on a street corner. She follows him as he stalks off and finds him waiting for her beside his blue box. She takes the opportunity to ask what species he is and he tells her he is a Time Lord.
He asks her if she’d like to take a trip with him but she is more concerned with her life at the moment and the problems she has to deal with. He then explains that he can travel in time as well, she wouldn’t miss anything. However the young human is sceptical and to prove it the Doctor disappears inside the box, which fades away with a deafening roar.
Martha steps forward in amazement at the now empty space, but the box soon returns and the Time Lord emerges, holding his tie. Martha remembers their encounter that morning and realises he has been telling the truth. She asks why he never used the opportunity to tell her not to go to work but he is adamant that established events cannot be interfered with, except for cheap tricks.
He tells her the name of the ship, the TARDIS, and then shows her inside. First marvelling at the massive space within she returns outside to examine the exterior, before asking if the extraordinary ship has a crew. The Doctor claims he is alone but occasionally brings along friends, most recently a girl named Rose who is now living happily with her family.
He is quick to establish that Martha is not a replacement for Rose, he is taking her on one trip only, as a thank you for her actions earlier in the day. She points out the kiss he gave her earlier on but he insists it was a genetic transfer and nothing more. She continues to point out the tight suit he is wearing and the fact that he travelled across the universe to flirt with her but he orders her to stop, and in return she claims she is only interested in humans.
Soon the Doctor is setting the ship in motion and with one last release of the handbrake the craft shudders to life, shaking violently as they cling onto the console.
“Welcome aboard Miss Jones”
“It’s my pleasure Mr Smith”