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42 was the seventh episode of series 3 of Doctor Who.

It marked Martha's first trip as an official companion to the Doctor as her previous travels were part of the Doctor's thanks for helping him in Smith and Jones. It also showed that Harold Saxon was interested in the Doctor and was using Francine Jones to get to him through Martha.

A prequel was written for this episode, entitled 42 Prologue. It was made available on the Doctor Who website.

From a production standpoint, it marked Chris Chibnall's first Doctor Who story. Chibnall was the head writer of spin-off series Torchwood, and would later become head writer and executive producer of Doctor Who from 2018 to 2022.


The Tenth Doctor and Martha follow a distress signal, only to be trapped on a spaceship hurtling towards a sun with only forty-two minutes left till impact.


In the TARDIS, the Tenth Doctor adjusts Martha's mobile phone, enabling it to call anywhere in time and space — an ability he refers to as Universal Roaming - as a "frequent flyer's privilege". As she is about to telephone her mother, Francine, they materialise on a very hot spaceship in answer to a distress signal. The Doctor notes that the spaceship's engines are not operating. They open the door to the next room and are pulled through by three members of the crew, who then slam the door shut. The captain, Kath McDonnell, explains that the engines have cut out and left the ship, the SS Pentallian, on a crash course with a local star. A nearby monitor announces that the projected time until impact is 42 minutes. The Doctor suggests evacuating the crew aboard the TARDIS, but the ship has begun venting excess heat through the room in which the TARDIS materialised, rendering it unreachable.

Meanwhile, the others move to the main engine room to try to fix the engines. The Doctor finds that all the engine-related machinery has been destroyed, and comments that the method suggests "someone knew what they were doing." He observes that they're in the Torajii system and that they're using energy scoops for fusion. He thought the scoops might have been outlawed by now; Kath assures him they were due for an upgrade. The Doctor organises Martha and Riley Vashtee to open a series of password-protected doors in order to access the control room where the auxiliary engines can be activated. He tells Martha to be careful.

The Ship's medical attendant, Abi Lerner calls the main engine room to say that Hal Korwin, the captain's husband, is having some sort of seizure. The Doctor tells everyone else to continue trying to save the ship, but Kath goes with him to the sickbay where they find Abi, Ashton, and Korwin. Korwin is lying near a stasis chamber with his eyes closed, screaming in agony, crying, "It's burning me!" before the Doctor sedates him. Once Korwin is unconscious, the Doctor instructs Abi to test Korwin to find out what is wrong with him; then the Doctor and McDonnell return to the rest of the crew.

While Abi is asked of Korwin's status, she states that he's heavily sedated and she needs more time, but she doesn't notice his hands twitching. When she returns to report some very strange results, she breaks off and the crew hears her screams for assistance as Korwin gets up and backs Abi against the wall, saying in a deep voice, "Burn with me". As he opens his eyes, a blinding light comes out and Abi screams in terror.


A mysterious woman listens in on Martha's phone call.

While the Doctor runs to Abi's aid, Martha and Riley are opening doors by answering pub quiz-style questions. Riley says they were set by the crew, years previously, after a night of drinking; but when the next question is to find the next in a series of what turned out to be happy prime numbers, the Doctor pops up on the comm with the answer. Riley observes that the crew has changed since they set the questions. The next question category is Classical Music, or, to Martha, 20th century Earth pop culture. The Doctor is both busy and not sure, so Martha rings her mother for help. Unbeknownst to Martha, Francine has knowingly had her call tapped by a young woman who is presumably a government agent. Meanwhile, the Doctor finds the imprint of Abi and concludes that she was instantly vaporised. He reads the medical reports and reasons that Korwin has been infected in some way, and can now vaporise people.

McDonnell is at first unwilling to believe that Korwin could be responsible for sabotaging the ship and killing Abi, but then relents and alerts the rest of the crew to avoid him. Ashton, working on the engines, sends Erina Lessak a message asking for more tools. She mutes the intercom and mutters under her breath about the injustice of being sent on every errand as she goes to the control cupboard. She sarcastically ends her spiel with "Just kill me now." When Erina closes the door, she turns to find a helmeted Korwin standing there. He then backs Erina against the wall as he did with Abi, and opens his visor to vaporise her.

Kath asks the Doctor not to lie about Korwin to spare her feelings. He tells her Korwin is too far gone, then demands to know if there is anything she is hiding. He thinks the attacks are provoked and personal. She says she knows everything about the ship and crew, and no one is hiding anything from her.

Next, Korwin goes to find Ashton, saying, "They are getting too far" and "we must share the light". Korwin grabs Ashton around the head, but instead of killing him, Korwin holds his gloved hands to his head, which begins to smoke.

A helmeted Ashton goes to Martha and Riley — presumably the ones who were "getting too far" — and tells them to "burn with me". He reaches for his visor, and they run for an escape capsule in terror and lock themselves inside. The capsule begins to jettison, and Martha calls for the Doctor.

Ashton tries to override the system and send Martha and Riley plummeting towards the sun, but Riley is trying equally hard inside the capsule to stop this from happening. Ashton finally just destroys the system when the Doctor arrives and tries to taunt him into raising the visor. At the same time, Korwin finds his wife, telling her, "It's your fault," before he is frozen by Scannell, prompting the possessed Ashton to ignore the Doctor and seek to continue Korwin's work. The Doctor calls them, explaining what's happening, but can't stop the pod; Martha and Riley jettison as she murmurs, "Sorry." The Doctor calls Scannell and demands a space suit.

In the capsule, Martha implores Riley to have faith in the Doctor, wondering why he has not found anyone in his life to have faith in — his family is all but gone and he has no romantic attachments. However, she is surprised when, in answer to her question, he looks directly at her and says, "I already have." Resigned to her fate, Martha phones Francine once more and, unwilling to divulge her predicament, instead tells her mother that she loves her and tries to get her to simply converse about her life until Francine's probing of whether the Doctor is with her causes a tearful Martha to end the call. Riley comforts her.

Scannell tries to talk him out of it, but the Doctor puts on his suit and goes outside to magnetise the ship in order to pull the escape pod back from the sun. Elsewhere in the ship, McDonnell lures Ashton into the medical bay and freezes him to death in the stasis chamber. Outside, the Doctor struggles to press the magnetic pull control buttons on the side of the ship, but he eventually manages it.


The Doctor is posessed.

Climbing back into the ship, the Doctor looks at the sun and stares into it, realising that "it's alive," before he too is infected by the same entity as Korwin. The escape pod returns to its launching point. Martha and Riley come back to the ship grinning until they see the Doctor writhing in pain. He cries for them to stay away, and they stand back in shock as his eyes glow before he tightly closes them. McDonnell arrives and the desperate Doctor angrily explains to her that because she illegally mined the sun for fuel, without checking for life signs, she has seriously injured the sun — scooped out the heart of a living being. Kath protests that he can't know, but he shouts that the sun is alive in him. She gasps and says checking takes too long and they would have been caught using the illegal fusion scoop. With his eyes still shut, he asks the two women to place him into the cryogenic stasis machine to take him below minus 200 to kill the sun entity in him before the entity uses him to kill them.

Korwin's body begins to twitch.

As Riley runs in, Scannell asks his favourite colour for the password, then shouts in protest when Riley isn't sure of the answer.

The women carry the Doctor to the med centre. Martha momentarily lets go of him to open the instructions, and he reaches out and calls for her in panic. She reassures him by repeating his instructions as Kath argues that he can't possibly survive the temperatures. Martha tells her he's an alien then shames her away, saying she's done enough damage. The Doctor frantically tells Martha he can only take ten seconds in the chamber. He cries in pain, saying it's burning him up, he can't control it, and "if we don't get rid of it, I could kill you. I could kill you all." He confesses he's scared and tries to tell Martha about a process which may happen if he dies; Martha assures him that he won't.

Martha starts the freezing process while the Doctor screams, but it is interrupted by Korwin, who turns off the power to the stasis chamber from the engineering department. The temperature had only reached negative seventy, as the somewhat frosty Doctor yells and continues to struggle with the invading entity. He then tells Martha that she must go to the front of the ship and jettison the fuel, which will return the living particles back to the sun. Martha protests, as she doesn't want to leave him, but she runs to tell the rest of the crew to jettison the fuel.

Elsewhere, a shocked McDonnell encounters Korwin. She admits to Korwin that this was all her fault and lures him to an airlock. She apologises to the rest of the crew through her radio, then opens the airlock and tells him that she loves him as the two of them are sucked out into space. Riley and Scannell work on the last door to open while Martha runs towards them. The defrosted Doctor collapses onto the floor and crawls into the corridor. He calls to Martha on the comms to say he can't fight it, "give it back or..." He opens glowing eyes as he finishes, "Burn with me." He screams. With only 58 seconds left until impact, Martha reaches Scannell and Riley as they realise the auxiliaries aren't working and tells them to vent the engines so as to dump the sun particles in the fuel. They're reluctant at first but she furiously shouts "NOW!" and they begin turning the dials to vent the engines.

As the fuel vents and replenishes the sun, the Doctor's eyes clear and the auxiliaries fire on reserves, freeing the ship from the gravitational pull of the living sun. The two remaining crew members hug, and Martha runs to find the Doctor and they hug too, both laughing in relief.

The Doctor and Martha head back to the vent room. Scannell and Riley marvel over the size of the unmarred TARDIS, and the Doctor advises they tell the authorities the truth, as the living sun needs care and protection. Martha kisses Riley goodbye. Inside the TARDIS, she tries to joke with a stoic Doctor, who stands there uncomfortably until she asks how he's doing, then abruptly breaks the moment with a suggestion – ice skating. Martha rolls her eyes and seems a bit hurt as she tells him she'll go where ever he'd like, then gasps as he gives her her very own key to the TARDIS, another "frequent flyer's privilege". The Doctor thanks Martha and smirks a little.

Martha calls her mother back, who invites her over for tea, and when asked informs her that it is Election Day. Martha accepts, saying she'll be around for tea, roughly. Francine hangs up, and the woman and two other men appear to be tapping Francine's phone again. Confiscating the phone, the woman asks Francine if she has voted. She says she has but doesn't say who she has voted for. The woman thanks her for all she has been doing, saying, "Mr Saxon will be very grateful."


Uncredited Cast[]


General production staff

Script department

Camera and lighting department

Art department

Costume department

Make-up and prosthetics



General post-production staff

Special and visual effects


Not every person who worked on this adventure was credited. The absence of a credit for a position doesn't necessarily mean the job wasn't required. The information above is based solely on observations of the actual end credits of the episodes as broadcast, and does not relay information from IMDB or other sources.


The Doctor[]

Galactic law[]


  • Mr Saxon is mentioned when Martha rings her mum.
  • Riley uses a Sierpinski sequence to lock Ashton out of the escape pod.
  • Scannell has trouble believing the TARDIS is actually a ship.


  • The episode occurs (approximately) in real time, like the American television programme 24. However, technically the events do not occur in real-time in this episode; for example, at the 03:45 mark, the timer is shown to read 40:26, which should mean that it would run out 44 minutes and 11 seconds into the episode. However, the timer actually runs out at 42:12, leaving 1 second short of 2 minutes unaccounted for.
  • The scene in which the Doctor promises to rescue Martha from the escape pod was inspired by The Last of the Mohicans.
  • The masks worn by the possessed crewmembers were inspired by Cyclops from X-Men.


  • The Doctor begins to tell Martha about his ability to regenerate.



  • Pentallian drives are a component of the ship.
  • The doors of the spaceship are deadlock sealed.
  • The stasis chamber aboard the Pentallian has a Cryofreeze.
  • A collision alert sounds aboard the Pentallian.



Story notes[]

  • The transmission was postponed to the 19th of May, rather than the 12th, because of the BBC's broadcast of the Eurovision Song Contest.
  • 42 is the approximate length, in minutes, of a new Doctor Who episode, which is the obvious source of the name, since the episode purports to be told in more or less "real time".
  • This episode has the shortest title of any televised instalment of Doctor Who broadcast to date and is the only one to date to consist solely of a number.
  • It was suggested that the story would be set in the same era as The Impossible Planet/The Satan Pit, and for a time, consideration was given to including the Ood, although this did not survive to the drafting stage.
  • Coincidentally or not, the Sun only possesses men, and those it possesses only kill women.
  • The stasis chamber from this episode is the MRI machine (redecorated) from Smith and Jones.
  • The muted horn musical tagline heard as we switch to Francine's home and see the three dark-suited individuals includes the four beat cadence later used in The Sound of Drums.
  • To promote the episode, Joseph Lidster wrote a short story entitled 42 Prologue focusing on Erina Lessak and the events leading up to the episode. The story, which expands on the backstory of Erina and other characters, was published exclusively on the BBC's Doctor Who website in May 2007.[1]
  • Miss Dexter makes her first appearance in this episode, although her name is not spoken. She's only referred to in the credits as the "Sinister woman".
  • The ship was originally called The Icarus. However, Sunshine, which opened around the same time, had a ship called The Icarus II. It was renamed The SS Pentallian, after the Pentalion drive mentioned in Revenge of the Cybermen.
  • The Doctor wears his blue suit for the entire episode however, once he exits the TARDIS and is on board the spaceship, the red lighting makes it look as though he is wearing his brown suit.
  • Ashton was originally called Motta, but it was felt that this would sound too similar to Martha.
  • The story originally took place in the Peony system, but it became the Toraji system following concerns that the original name would be misheard as "penis".
  • A major set piece involved the Doctor scaling the exterior of the spaceship, until fears were raised about the expense it would incur. Chris Chibnall simplified this to the Doctor's efforts to reach the lever outside the airlock.
  • Some of the sound effects in this episode were taken from The Hitchhiker's Guide to the Galaxy.
  • Michelle Collins filmed her death scene on the first day of shooting.
  • Martha Jones gets her phone upgraded and a key to the TARDIS, two signs that she's the new companion.
  • David Tennant would later star in Chris Chibnall's crime series Broadchurch.
  • It was suggested that this might be a sequel to The Impossible Planet/The Satan Pit, revisiting Zachary Cross Flane and Ida Scott, as well as the Ood.
  • At any early stage, the story was set on a research space station which had been studying the same sun for generations; the crew had grown up on board. A major plot twist would be the revelation that the sun harboured sentient lifeforms, although Russell T Davies was concerned that the crew's ignorance of the presence of these entities might seem ridiculous.
  • Russell T Davies noted that, although there had been several episodes of the revived series set on space stations, none had taken place entirely on a spaceship. Furthermore, this setting was cheaper to realise.
  • Originally, Martha was infected by the solar entity, but Russell T Davies felt that it would be more effective if the Doctor suffered this fate, with Martha playing a crucial part in resolving the situation.
  • Korwin's death was first portrayed as the result of a calculated decision by Captain McDonnell, but this was deemed too ruthless. Chris Chibnall duly revised the events so that McDonnell was left with no other choice.
  • Vashtee was originally called Kincade, until Russell T Davies decided to use it as Brannigan's middle name in Gridlock. His first name, Riley, was shared with Chris Chibnall's godson.
  • Russell T Davies wanted the episode to mark the stage at which Martha stopped being a guest aboard the TARDIS and became an established companion. This would be particularly important because the next story, would literally see the Doctor entrust Martha with his very identity. As such, Chris Chibnall was asked to give her a pivotal role in his adventure.
  • A major set piece involved the Doctor scaling the exterior of the ship, until fears were raised about the expense it would incur. As a result, Chris Chibnall replaced the sequence with the simpler action of the Doctor trying to reach the lever outside the airlock.
  • The episode formed the seventh production block of season three, along with Utopia. It was originally intended that 42 would be largely completed before Graeme Harper turned his attention to Utopia, but the order was reversed when it was discovered that Derek Jacobi would be unavailable for the revised filming dates. 42 was duly brought forward, forcing the design teams to work feverishly to get sets, props and costumes ready in time.
  • The St Regis Paper Company mill was actually quite chilly, prompting the actors to employ various tricks to keep their breath from steaming.
  • Miss Dexter's role was supposed to be Mysterious man from The Lazarus Experiment, but Bertie Carvel wasn't available.


  • 7.0 million (overnight ratings)
  • 7.41 million (UK final)[1]
  • 0.89 million (BBC3 repeat)

Filming locations[]

  • St. Regis Paper Company, Sudbrook, Caldicot
  • Cwrt-y-Vil Road, Penarth
  • Nippon Electric Glass UK (now known as Trident Park/part of Trident Park), Cardiff Bay
  • Upper Boat, Tonteg Road, Treforest Industrial Estate, Pontypridd

Production errors[]

If you'd like to talk about narrative problems with this story — like plot holes and things that seem to contradict other stories — please go to this episode's discontinuity discussion.
  • As Martha takes off her jacket, right after stepping out of the TARDIS, it seems she's wrapping it around her waist and then it's gone.


Home video releases[]

External links[]