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Terminus was the fourth serial of season 20 of Doctor Who. It was the final regular appearance of Sarah Sutton as Nyssa, who parted company with the Doctor at the conclusion of part four. It was the second story in the Black Guardian trilogy.

It featured the last appearance of a four-person regular TARDIS team on the show until 2018's The Woman Who Fell to Earth where the Thirteenth Doctor joined forces with Yasmin Khan, Ryan Sinclair and Graham O'Brien.


Still under the malign influence of the Black Guardian, Turlough sabotages the TARDIS, placing the Doctor and his companions in grave danger. Nyssa disappears through an unstable interface with a nearby space liner, and the Doctor begins a desperate search for her aboard the ship.

When the liner docks at Terminus, a space station at the exact centre of the universe, the horrific truth starts to emerge. It may be already too late to save Nyssa's life, and the existence of the entire cosmos is now at peril...


Part one[]

Under the direction of the Black Guardian, Turlough manipulates the TARDIS' circuitry in a corridor. Hearing Tegan approach, he hurriedly shuts the roundel he was working behind. Tegan, still suspicious of the new companion, finds him and questions him, her mistrust only exacerbated by the roundel falling open again. When Turlough tries to turn on the charm, Tegan shows him to his room, formerly Adric's.

Once Tegan has left to find Nyssa and complain about his obnoxious personality, Turlough heads to the console room to remove the space-time element from beneath the console. The Black Guardian appears on the scanner screen to encourage his obedience, despite his doubts that the Guardian will preserve his life. While Turlough is unable to remove the element, his sabotage causes the TARDIS to begin breaking up.

Tegan sees one of the fractures in the corridor and runs to find the Doctor. Another fracture appears in Nyssa's quarters. While the Doctor frantically tries to save the TARDIS, the fracture in Nyssa's room resolves into a door with a mysterious skull logo on it. Deciding that the unknown on the other side of the door is better than the certain death in her room, the Doctor tells her to run through the door.

The Doctor, Tegan and Turlough run to Nyssa's quarters. The Doctor throws a chair into the door to keep it from closing and severing the link to the space vessel that the TARDIS, engaging an emergency system, has locked onto. The Doctor goes through the door and tells Tegan and Turlough to stay. After a few minutes, Tegan goes through. The Black Guardian tells Turlough to go through and to kill the Doctor. Once Turlough gets through the door it closes behind him.

The Doctor goes ahead to find Nyssa. Tegan and Turlough aren't sure which way the Doctor went. Nyssa, hearing someone coming up behind her, hides. It is the Doctor, though, and he finds her. Meanwhile, two space pirates, Kari and Olvir, board the ship and make their way to the bridge, finding it deserted and running on automatic. Hearing a sound she believes to be Nyssa, Tegan drags Turlough along to help find her. They find a locked door that the voice is coming from. Tegan tells Turlough to find a pry bar and works to try to open the door. While he's away, he hears her yell and comes back to find robed arms trying to pull her inside the door. He helps her to get free of the arms.

On the bridge, Kari and Olvir have taken the Doctor and Nyssa prisoner, believing them rival pirates. Unexpectedly, Kari and Olvir's ship undocks and accelerates away. While Kari tries, first by force and then by negotiation, to persuade the Doctor to take them with him, a computer voice suddenly comes to life. It announces that they are soon to dock at Terminus and all passengers should disembark to avoid an imminent sterilisation.

Olvir realises what this means: the passengers locked in their rooms all have Lazar's disease and they are trapped on a plague ship.

Part two[]

As the ship docks with Terminus, Turlough and Tegan take shelter under a grating in the floor of the corridor to escape the diseased Lazars. The Doctor warns Nyssa not to touch the Lazars and stops Kari from shooting them. The three of them head to the bridge to find Olvir. Nyssa finds him cowering behind a chair.

While Tegan finds a ladder out of the underdecks, Turlough hears the voice of the Black Guardian warning him not to fail in assassinating the Doctor. On the bridge, Olvir explains that his sister died from Lazar's disease. He tells them that Terminus is run by a private company, for profit, that uses fear of the disease to demonise the plague victims. While they claim to offer a cure at Terminus, he's never heard of anyone coming back. The Doctor, meanwhile, is stunned to discover Terminus is in the centre of the known universe.

Tegan and Turlough, still under the floor, see an armoured man patrolling the deck. He gives an order: "Sterilise!"

Nyssa is taken

Nyssa is taken.

Within Terminus, Bor is studying a display and muttering, "The reading's still climbing." Valgard, the armoured man from the ship, enters and is horrified to see Bor crossing a line demarcated on the floor. He goes to follow but stops at the line. Instead, he reports to his commander, Eirak, that Bor has entered the Forbidden Zone, only to be horrified at Eirak's insensitivity and fatalism at their situation.

On the bridge, the computer warns that sterilisation is imminent. Noxious gas flows through the underdecks where Tegan and Turlough are still trapped. The Doctor's entourage on the bridge decide to try to find the entrance to the TARDIS. Nyssa begins to feel feverish, necessitating the removal of her skirt. Realising that she's infected, Olvir recoils, only to see her dragged away by a robotic drone.

Nyssa is brought to Valgard, who is complaining to Sigurd, another Vanir, about Eirak's insensitivity. Referring to himself as a "baggage handler", Valgard himself is insensitive to the plight of the Lazars, caring only for the Hydromel on board the ship. While Sigurd retrieves the Hydromel, stealing a vial to insert in his armour, Nyssa attempts to flee Valgard. Unknowingly, she gives Olvir a chance to slip aboard Terminus. Valgard takes her to meet the Garm. Shortly afterwards, the Doctor finds Nyssa's skirt.

Eirak, resigned to Bor's death, has Valgard call the Garm (a large humanoid with a dog-like head) to ensure that Bor's armour is recovered. The Garm is summoned by a small call box and emerges from the Forbidden Zone.

Not knowing what happened to Turlough and Tegan, the Doctor and Kari flee to Terminus, unknowingly observed by Valgard. He knocks Kari down and then grabs the Doctor by the neck and begins to squeeze...

Part three[]

Kari regains consciousness and goes for her gun. Valgard uses the Doctor as a shield, so she ricochets the shot from her gun off some nearby scrap metal. The gun's powerpack drained, Kari and the Doctor flee into the Forbidden Zone.

While Olvir steals a Vanir helmet and robe to move around undetected, Tegan and Turlough finally escape from the crawlspace. Trapped with the Lazars, Nyssa appeals to the Vanir for help, to no avail.

Eirak discovers that some of the Hydromel is, in fact, coloured water. Valgard bursts in, reporting of his encounter with the Doctor and Kari. He challenges Eirak's leadership, and Eirak contentiously agrees that, should Valgard return from the Forbidden zone with the intruders captive, Eirak will step down as the leader.

While Nyssa presses one of the Lazars for information, Olvir is detected as an intruder, and Eirak leads a party to find him. However, they find a decoy Olvir had left, and Eirak believes there is no intruder. Seeing to the Lazars, Eirak decides that Nyssa will be the first to be treated.

Exploring the Forbidden Zone to find the source of the radiation they've detected since arriving, the Doctor and Kari come across Bor, now severely burned and in a fragile mental state, lugging a load of scrap metal behind him. Bor leads them to the engines that drive Terminus, one of which is damaged and leaking radiation; he's been piling metal in front of it.

Valgard vs Doc

Valgard attacks the Doctor.

Bor, struggling to focus despite his memory loss, warns the Doctor that if the damaged engine is to explode, it would threaten the entire universe. He also says that one engine has already exploded, a "long time ago". Telling them to check the computer and follow the cables, his explanation is interrupted by Valgard.

Sure that the Doctor and Kari are spies from Terminus Incorporated, Valgard attacks the Doctor with his staff. The Doctor parries and knocks Valgard into the metal Bor had been stacking around the engine. The Garm arrives and picks up the weakened Bor.

Meanwhile, Nyssa is chained up at the entrance to the Forbidden Zone, and Eirak summons the Garm to take her to her mysterious cure. The Garm, still carrying Bor, enters at the same time Olvir arrives to try to free Nyssa. Unable to free Nyssa, he instead tries to shoot the Garm, only to find his blaster completely ineffective. The Garm takes Nyssa away; Olvir follows them into the Forbidden Zone.

As the Doctor tries to follow the cables that Bor mentioned, Bor himself is being questioned by Sigurd. While still confused due to his radiation sickness, he mentions that the pilot of Terminus is dead and that if he fires up the engines, the Big Bang will happen all over again. Eirak denies the dying Bor any Hydromel, thinking it to be a waste of their limited supply.

Turlough appeals to the Black Guardian for help getting back to the TARDIS. The angry Guardian at first punishes Turlough for his failure to kill the Doctor, then reluctantly tells him how to recreate the door to the TARDIS. He and Tegan, the latter of whom is still unaware of Turlough's bargain, head back to the ship's crawlspace.

As the Doctor and Kari reach Terminus Control and find the corpse of the pilot, Olvir discovers the Garm chaining Nyssa up in the engine room. He rushes to her, only to be caught off guard by Valgard. Turlough, meanwhile, has discovered the circuitry that the Black Guardian indicated; his manipulations of it result in a shower of sparks.

The Doctor discovers that Bor's description was not accurate in saying a previous engine had exploded. In fact, Terminus was a time ship that had dumped its fuel while in time-flight to avoid an overload. The fuel, dumped into a void, had started a chain reaction, resulting in the biggest explosion ever: Event One.

Deducing what had happened, the Doctor comes to a terrifying conclusion: while the exploding fuel had created the universe, the same events occurring now would undoubtedly destroy it. He also makes a second discovery: that the fuel dump process was automatically started by the computer - a process that has just begun.

Part four[]

Valgard and Olvir continue to fight, while the Garm takes Nyssa away. The younger and healthier Olvir defeats Valgard, only to realise Nyssa is gone. Turlough and Tegan, meanwhile, see the door to the TARDIS begin to reappear and return to the circuitry in the crawlspace.

Olvir attempts to retrieve his gun from the pool of radiation generated by the engine. Valgard comes to and warns him not to try, lest he receive a fatal dose of radiation. Valgard reveals that, like Olvir, he was once a pirate, and learned combat from Olvir's commander. That commander later betrayed Valgard, turning him in for a reward and condemning him to a life of slavery on Terminus. Valgard begs Olvir for sympathy, but he ignores him to find Nyssa. After Olvir leaves, Valgard stands, revealing his ploy to be a ruse, and retrieves Olvir's abandoned gun by using his staff.

The Doctor and Kari are struggling to throw the switch to stop the fuel dump, but are unable to get it to budge. Meanwhile, Turlough and Tegan's work in the crawlspace is interrupted by an announcement from the computer: the Starliner is beginning to move. Tegan runs to the bridge to attempt to stop the departure. The computer ignores her protests as the engines begin to glow.

Turlough, alone in the ship's corridor with the door back to the TARDIS fully materialised, smiles to himself. On the bridge, the computer announces the launch is being aborted. Turlough runs to the TARDIS console room.

Nyssa awakens in a white chamber to discover all the symptoms of Lazar's disease are gone. In Terminus control, Kari watches the Doctor struggle with the control and observes aloud that the pilot must have had the strength of a giant. The Doctor has a realisation: the Garm!

In the console room, Turlough is again berated by the Black Guardian for the Doctor's continued presence in the universe of the living. Turlough's crystal begins to glow.

Olvir confronts the Garm about what he does to the Lazars. The suddenly loquacious Garm defends his actions as saving some that would otherwise die and takes Olvir to Nyssa. Sigurd, meanwhile, decides to steal some Hydromel to ease Bor's pain.

The Doctor and Kari summon the Garm. Olvir forces his way into the chamber in which Nyssa is recovering, and is rewarded for his efforts by Nyssa throwing him to the ground and straddling him ready to strike. Nyssa has realised that the "cure" of radiation could work consistently if it were properly studied.

As the engine continues to build to overload, the Garm begins to force the override lever back. Terminus itself begins to shake. At first, even the Garm's strength seems insignificant, but eventually, he manages to push it back. After it is shut off, the Doctor disconnects the computer from the system. The Garm pleads for something in return: his freedom.

Nyssa makes her goodbyes

Nyssa makes her goodbyes.

The Doctor smashes the box that controls him and leaves to finish the shutdown of the engine. Valgard ambushes the Doctor and Kari, only for them to be rescued by Olvir and Nyssa. Nyssa believes that the Garm, now free, could help her improve the treatment of the Lazars. Valgard protests that, even if this were true, the Terminus Corporation wouldn't care, and as long as they control the Hydromel, the Vanir are slaves. Nyssa, however, realises she could synthesise and even improve the Hydromel. The Corporation would be unable to retaliate since the soldiers they might send would never enter a Lazar colony. Like the Garm, the Vanir are now free.

Eirak returns, and Valgard produces the Doctor, reminding Eirak of their deal. Sigurd supports Valgard, and even Bor says, "It's time for a little chat."

As the Doctor advises Valgard on how to improve Terminus, Nyssa makes an announcement: she is staying at Terminus to help the Lazars. With a kiss on the Doctor's cheek and a hug for Tegan, her life has changed.

Turlough slowly wakes up on the floor of the console room, as the voice of the Black Guardian echoes through the room: "This is your last chance, boy... Kill the Doctor!"


Uncredited cast[]



Diseases and illnesses[]


  • Nyssa recalls that Adric used to perform the calculations she needs for her experiments.
  • The Vanir are slaves of the Company.


  • Drones are used on Terminus to sterilise the vessels that dock there.


  • Terminus is at the centre of the known universe.
  • The Terminus craft was once capable of time travel. When one of its jettisoned fuel pods exploded in a void, it caused a chain reaction. The ripples followed the craft through time, throwing it billions of years into the future.


  • The Doctor's TARDIS' space-time element is beneath the console. The Black Guardian calls it the heart of the TARDIS.
  • Turlough is given Adric's room in the TARDIS.
  • When the TARDIS is threatened with break-up, it will attempt to lock onto the nearest safe place in space-time (in this case, a Starliner), to allow its passengers to escape. The Doctor claims it has always had this protocol, but it's never worked before.

Story notes[]

  • This story has one of three descriptions of how the universe started; the others are in TV: Castrovalva and AUDIO: Slipback. As the exact fuel used by Terminus is never mentioned, but apparently produces radiation as a side-effect of energy generation, it's plausible to believe that Terminus is fusion-powered by hydrogen and its release of fuel and the in-rush of hydrogen mentioned in Castrovalva are the same event.
  • This story is well-remembered for its controversial (at the time) scenes in which the conservative Nyssa gradually removes some of her clothes, leaving her in little more than a shift by the story's end. Sarah Sutton later claimed that it was a "parting gift" to her male fans.
  • Strangely enough, despite the grim tone of the story and its themes of disease and death, it is the only story from season 20 in which no-one dies.
  • Hydromel comes from two ancient Greek words — the word for "water" and the word for "honey". Hydromel translates as honeyed water or mead.
  • Martin Muncaster's role as the voice of the spaceship's computer was credited as "Tannoy Voice" under the mistaken belief that "tannoy" was a generic term for a public address system. Shortly after part one aired, the production office received a letter from Tannoy Ltd. pointing out that the term "Tannoy" was actually a registered trademark referring to products manufactured by them.
  • Tegan and Turlough do not have anything to do with this story's main plot, and they hardly interact with any of the guest cast members.
  • Until 2018's The Woman Who Fell to Earth, this was the last television story to have three regular companions. This is excluding stories like TV: Boom Town and TV: The Impossible Astronaut which had Mickey and River respectively as major supporting characters and who could be argued are companions for those stories.
  • This is one of the only stories where the TARDIS interior is seen, but not the exterior; and is also the only story in which the TARDIS's chameleon circuit functions correctly.
  • Mark Strickson thought the leper colony idea was sick, while Peter Davison felt it didn't go anywhere.
  • Originally, the Doctor and Nyssa were supposed to shake hands as they parted, but Peter Davison and Sarah Sutton decided that he should kiss her on the cheek instead.
  • Sarah Sutton cried real tears when she hugged Janet Fielding during her goodbye scene.
  • The pilot had originally been dressed with cobwebs. Peter Davison objected, observing that the pilot was not meant to be dead but simply moving very slowly, and Mary Ridge accordingly ordered them removed.
  • Nicholas BallTom Chabdon, Paul Darrow, Michael Gothard, Del Henney, Bernard Hill, Patrick Mower, Patrick Stewart, Anthony Valentine and David Warner were considered for Valgard.
  • Sean Arnold, Nicholas Ball, Ralph Bates, Christopher Cazenove, Tom Chadbon, Ben Cross, Jack Galloway, Nigel Havers, Richard Heffer, Martin Jarvis, Jeff Rawle, Patrick Ryecart, Paul Shelley, Simon Ward and Simon Williams were considered for Eirak.  
  • The production was fraught with technical difficulties, including problems with costumes, delays due to electrical problems and a mis-built set. The result was that some scenes had to be recorded on improperly-lit sets, production ran seriously late and several scenes were taped hastily, much to Peter Davison's frustration.
  • An industrial dispute between the BBC and the electricians' union resulted in a major reorganisation of shooting schedules. As a result, the crew had to work against the clock to complete the story.
  • Miscommunication with Rod Vass of freelance props firm Imagineering led him to believe that the Vanir armour he was asked to fabricate would be purely decorative. He was therefore shocked to learn upon delivery that they would be required for combat. The costumes proved to be extremely noisy when involved in vigorous activity, and costly refurbishing was required to address the problem.
  • Because part one underran, Eric Saward asked Stephen Gallagher to to provide two new one-minute scenes. Unfortunately, Gallagher misinterpreted the request and instead extended several existing scenes to fill out two minutes' worth of material. Consequently, Gallagher's amendments were discarded.
  • The first day of filming was plagued with problems. A power failure resulted in a two-hour delay. When the crew was finally ready to go, Mary Ridge discovered that one set had been erected off its marks, incurring a further stoppage. Then, John Nathan-Turner was forced to call a halt to the recording of scenes involving the interior of the TARDIS console because the correct circuitry was missing. This meant that Ridge had to record sequences on other sets which were not yet properly lit. Later, it was learned that neither of the drone robot props had been tested before being brought into the studio, and indeed only one of them was found to work correctly. Despite all of these disruptions, Ridge was able to complete almost all of the scenes set within the TARDIS and the adjoining liner corridor.
  • Many scenes were rushed through with only one take and little to no rehearsal, as Ridge had never once exceeded her allotted shooting schedule in her career, and had no intention of losing that record. Which, unfortunately, she did anyway after the various other problems proved too much for to recover from, forcing the team to schedule another couple of days of filming the following week... right after Sarah Sutton's farewell party.
  • Stephen Gallagher felt that this was a much greater intellectual experience than his previous script, describing it as "a sober affair compared to the box of firecrackers that is Warriors' Gate".
  • Eric Saward felt that the script would be better suited to a film and that it lacked dialogue.
  • Stephen Gallagher had wanted the Garm to look spooky and also to only be seen in shadows. He was surprised when it was fully realised. According to Liza Goddard, the Garm costume was so hot that the actor inside (R.J. Bell) fainted several times during recording.
  • The costumes were called into question, as they clearly impractically designed for fighting. Peter Davison described them as "copulating crabs" and "like a rock tribute band".
  • The opening and closing scenes were written by Eric Saward.
  • Peter Davison named Nyssa as his favourite companion and he was upset that Sarah Sutton was leaving, while she didn't leave of her accord and didn't want to go.
  • Visual effects designer Peter Pegrum was responsible for Kari and Olvir's helmets, which he thought were only to be carried, and never worn. When Liza Goddard and Dominic Guard donned the headgear, they quickly found that a lack of air holes meant that the helmets easily fogged up, necessitating modification.
  • One of the extras playing a Lazar accidentally grabbed at Janet Fielding's top during a scene, causing her to expose herself.
  • Steve Gallagher took inspiration from Norse mythology, naming the Vanir after a lesser group of fertility gods. Of the individual members, Bor was the father of Odin, head of the Norse pantheon; Sigurd was a great Norse hero, also known as Siegfried or Sivard Snarensvend; and Eirak was initially called Eirik, after a king of Norway and Northumbria also known as Eric Haraldsson or Eric Bloodaxe. Similarly, the Garm was named for a monstrous hellhound, also known as Garmr, who appeared during the time of Ragnarok, the twilight of the Norse gods.
  • The term Lazar was an archaic word for “leper”; it was derived from the Biblical figure of Lazarus.
  • The instability in the TARDIS was originally caused by an experiment Nyssa was conducting, rather than being Turlough's handiwork.
  • Kari was originally named Yoni, until Eric Saward observed that this was the Sanskrit word for the female reproductive organ.
  • Originally, Kari contracted the Lazar disease in part three. Bor initially perished in the same instalment.
  • Steve Gallagher wanted to hint at an underlying sexuality to the relationship between the Doctor and Nyssa.
  • Sarah Sutton was very disappointed with her final story, and could not understand the rationale for Nyssa removing her skirt.


  • Part one - 6.8 million viewers
  • Part two - 7.5 million viewers
  • Part three - 6.5 million viewers
  • Part four - 7.4 million viewers


  • This story was originally to have featured the Ice Warriors. (It wasn't, although there was talk of the Ice Warriors reappearing during Season 20.)

Filming locations[]

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.
  • When the Garm asks if it has done well in part four, R. J. Bell's neck is visible beneath the head of the Garm's costume.


Home video and audio releases[]

DVD releases[]

This story, Mawdryn Undead and Enlightenment were released in The Black Guardian Trilogy Boxset on 10 August 2009.


  • Commentary by Peter Davison (the Doctor), Mark Strickson (Turlough), Sarah Sutton (Nyssa) and Writer Stephen Gallagher
  • Breaking Point - Cast and crew look back at the making of this story
  • Origins of the Universe - Sir Patrick Moore and Dr John Mason take a look at the science behind the Big Bang and the origins of the universe
  • Original Storyboards - Production storyboards for the spaceship sequences
  • Unused Model Shots - A selection of unused takes from the model effects shoot
  • New CGI Effects - The option to watch the story with many of the original video effects sequences replaced by new CGI
  • Continuity - Original BBC-1 continuity announcements
  • Radio Times listings (DVD-ROM - PC/Mac)
  • Isolated Score
  • Production Information Subtitles
  • Photo Gallery
  • Coming Soon Trailer - The Twin Dilemma
  • Easter Eggs:
    • TARDIS Information File. To access this hidden feature, press down at Menu on the second page of the Special Features menu to reveal a hidden Doctor Who logo.
    • VT countdown for all four episodes. To access this hidden feature, press up at Audio Options on the Special Features menu to reveal a hidden Doctor Who logo.

Box set[]

It was released as issue 140 of Doctor Who DVD Files.

Video releases[]

  • This story was released on video in 1993 in episodic format in UK and Australian markets and 1994 in US markets.

Digital releases[]

  • The story was released to download on iTunes.
  • It is also available for streaming in Canada & the US through BritBox or Amazon Instant Video in the UK.

External links[]