User:DoctorQuoi/sandboxMainRange2

Part one
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Part two
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Part three
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Part four
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Continuity

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Part one
In 1908 Adela Forster attempts to escape from some unseen threat with her son Jonathan Forster, however he is taken by the unseen threat and she barely manages to escape.

The TARDIS materialises in 1926 on a train platform and has brought the Doctor, Tegan, Turlough and Nyssa to Calcutta, India, on the Doctor's insistence they watch the famous cricket match between All India and Marylebone Cricket Club. Before they can go to the match, however, Nyssa is attacked and bitten by Kimball, a chauffeur and friend of Professor Narayan, after she tries to calm him down while he makes a commotion on the platform and in the meantime the Doctor sends Tegan to gets medical supplies from the TARDIS so they can help him as he realises the man has been infected with what appears to be rabies. It is too late though when he is shot and killed by Major Cyril Haggard arrogantly claiming to an appalled Doctor that he was taking care of the situation and saving their lives before he boards the train. The Doctor believes Nyssa has been infected with rabies but if he can treat it quick enough she should be fine while he tries to bring Nyssa back to consciousness. Professor Narayan explains the situation while a delirious Nyssa slowly comes to and Tegan bumps into a mysterious man and later finds the TARDIS gone from where they had left it, and returns to inform the Doctor. They spot it on the train which is leaving the station, so the Doctor instructs Tegan and Turlough to get aboard and remove it or at least get the medical supplies at the next station and that he and Nyssa will follow them on the next train.

Aboard the train, Major Haggard finds and confronts Adela Forster, claiming he is taking over the train despite her attempts to throw him off, claiming she rented out the entire train. Tegan and Turlough, meanwhile, find themselves locked in a cage with a dangerous tiger. The Doctor, Nyssa and Professor Narayan drive Professor Narayan's Rolls-Royce Silver Ghost after the train when suddenly Nyssa tells the Doctor she's seeing double, except that she can both see them chasing the train but she can also see Tegan and Turlough in front of her, screams that the tiger with the emerald eyes is going to kill them, grabs control of the wheel in an attempt to catch up with the train and save them but the car ends up careering out of control...

Part two
The Doctor is awakened by Professor Narayan and they find that Nyssa has slipped into a coma. He comments that it is unusual because when Kimball was bitten, he didn't have the same reaction. The Doctor reckons it is due to Nyssa's different metabolism, while the Professor explains the circumstances behind how Kimball was bitten, because he was investigating the Karabar Caves, since his field of expertise is mythology and folklore and the caves are his favourite place to do research. Despite the car being broken, they find an air balloon owned by Colonel Burroughs and "borrow" it, deciding to go to the Karabar caves the source of the bites. Tegan manages to slip out of the car to find the owner of the tiger so that they might muzzle it so Turlough can get out in one piece. She finds Major Haggard and Adela Foster, and explains what happened. Turlough, meanwhile discovers the tiger is named Dawon and can talk as it shares a mind with Nyssa and it recognises him as a friend and explains the situation. Tegan, the Major and Adela arrive and the tiger tells Turlough not to reveal it can communicate with them. Adela explains to Tegan that there are no other stops on their route and she goes to check on the TARDIS, while Adela explains to Turlough that they are headed to the Karabar caves.

Professor Narayan explains the mysteries of the caves to the Doctor as Adela explains to Tegan how her husband Edgar Forster, a naturalist, went exploring to try and find the fabled city where creatures were made of crystals and he brought her and their son Jonathan with them, wanting to find it and make a name for himself as a great scientific discovery. However, she ended up losing both of them but in a last-ditch effort managed to seal the cave's entrance, saying that something evil was located at its center in order to stop it escaping. Years later, when word reached her about a tiger with "crystal claws", she realised that the creature in the cave had found a way out and has now returned, with a train full of dynamite, to properly finish the job. In the meantime, Major Haggard lets himself out and locks the compartment from the outside, claiming that since Adela has seen his briefcase full of money and they know of his presence, they know too much as he is a thief and does not want to be caught. He then kills the driver and sets the train to crash through the station and go off the mountain, killing all witnesses and allowing his getaway. He is thrown out by Tegan, however, she cannot stop the train. Nyssa awakens and instructs the Doctor on how to find them, which they manage to by turning the balloon into a high-powered ship. Tegan spots the Doctor and guessing the situation, he uncouples the cables holding the cars together in an attempt to stop the whole train from going through the station and over the cliff but it seems too late...

Part three
The Doctor manages to uncouple the car and save Turlough and Lady Adela but the front of the train ends up going through the cliff and Tegan is presumed dead. Meanwhile the hot air ballon, containing a grieving Nyssa over Tegan's apparent demise and a consoling Professor Narayan over-shoots the station and ends up descending down into the depths over the cliff, with the Doctor promising Nyssa he will come rescue her. In her last words, she tells the Doctor to talk to the tiger. Turlough finds the Doctor and explains everything while Major Haggard, having been jettisoned, comes to, fixes his shoulder and prepares to go to the caves on foot. The Doctor talks to Dawon and he, the tiger, Turlough and Lady Adela set out to find Nyssa and Professor Narayan. Meanwhile, suspended in the hot air balloon as it has crashed in the trees, Professor Narayan realises he is back where he came from and explains to Nyssa his back-story, as he is Ayyappan the destroyer, the sister of Dawon and brother of Shardul Khan. Meanwhile Dawon finds and attacks Haggard but he shoots her and escapes, while the three find her and the Doctor attempts to help her recover. Haggard is found by the Doctor and escapes but supposedly finds his demise at the beetle's, whose bite can kill. Adela lights a fuse on a stick of dynamite she brought to try and stop the beetles escaping the cavern in fear. A snake attacks Nyssa in the balloon and Professor Narayan saves her at the cost of being transformed and he warns her to run away as he will soon lose control of himself and begin chasing her.

The four discover that the water they saw earlier is actually because of a lake nearby and the dynamite set off by Adela 10 years ago and just now have caused the fissures to tear and Dawon is swept away by the incoming current while Adela goes after her, followed by the Doctor and a reluctant Turlough in the stream. They manage to save Dawon who tries to find Nyssa using their connection. Meanwhile Nyssa is found by the other wolves in the cavern and begins to change due to the curse of the 'Emerald Tiger'. However, she is found in time and at first is saved by the Doctor, Turlough, Adela and Dawon. However, they begin losing to wolves until they are chased away by an elephant one of whose rider is revealed to be Tegan...

Part four
Tegan explains how she survived, first taking shelter inside the TARDIS as the Doctor he given her the key earlier to survive the train crash, after which she was found by Djahn. He helps her to find the others and is reunited with his mother Adela, as they realise thanks to the book with Djahn (which happens to be "The Jungle Book") that he is Jonathan. Nyssa surmises that Dawon raised Jonathan due to her motherly instinct while her brothers merely sought death and destruction. In the meantime they try to find Dawon and the Professor, who it transpires are being held captive by Shardul Khan who has swallowed them as he has, after years of separation from his brother and sister, absorbed the emerald tiger and plans to take control of the entire kingdom. While discussing what happened, the Doctor realises that the jungle's perimeter is similar to an impact crater and realises that the resulting life forms, a fusion of flesh and mineral materials, is likely the result of the emerald tiger which he then realises must not be from Earth. Nyssa begins to suffer headaches as her mental connection is strained while Dawon and Ayyappan battle Shardul for control of the emerald tiger. They find a temple and make their way inside while Shardul kills Dawon and Ayyapan. The Doctor explains that the emerald tiger may be the exceedingly rare and fragile mineral homogenite and hence responsible for the strange fusion of beast and mineral in this jungle. They are cornered by Shardul Khan but the Doctor tries to taunt him, however, Adela lights dynamite and places it next to the crystal, and threatens Khan (who was distracted by the Doctor) with its destruction (which will destroy him). The Doctor instructs Turlough and Tegan to take Adela and an injured Jonathan (who attacked Khan after discovering that Khan had killed his foster mother Dawon) out of the cave and get to safety in the TARDIS. Nyssa holds off Khan and instructs the Doctor to leave despite his protests as she begins transforming again against her will, hoping to use the last of her mental connection to the absorbed Dawon to hold off Khan until the dynamite goes off and destroys the crystal, finishing him off for good. The dynamite goes off and the crystal is destroyed, taking Khan with it.

They manage to find Nyssa buried in the rubble after the destruction of the temple and find that the detrimental effects the crystal had been inflicting on her have been halted and have disappeared, although she seems to have become rejuvenated and looks as she did when she stopped traveling with the group before to stay on Terminus. Adela decides to stay with her son Jonathan and live with him in the jungle and the four head back to the TARDIS.

Continuity

 * When Professor Narayan explains that the Karabar caves and their mysterious activity are inexplicable, the Doctor corrects him by saying "not inexplicable, only unexplained". The fourth Doctor said the same thing to Leela who thought a yo-yo was magic until the Doctor corrected her. (TV: The Robots of Death)
 * The Doctor quotes Isaac Newton's First Law of Motion and after claims "You've never let me down Isaac". The Doctor has met Issac Newton on a few occasions, and even once tried to explain the concept of gravity to him. (TV: The Pirate Planet et al, AUDIO: Summer et al.)
 * The Doctor tells Lady Adela "brave heart", something he often told Tegan. (TV: Earthshock et al.)

Part one
The Doctor, Tegan, Turlough and Nyssa land on a colony in the year 3556 due to the TARDIS being brought there by a signal. They meet Sibor who explains to them about the chronoscope and that their planet Valderon is governed by the predictions of the chronoscope and that people are arrested before they commit the crime. She also explains that the planet is in quarantine as it is a place for researching a treatment for Richter's syndrome, and the prisoners on the planet are used as scapegoats for testing cures. They are greeted by Galen (really Adric Traken, who uses the pseudonym as he saw his mother earlier and mistakenly thinks that he is meeting her at an earlier point in her life before she stayed on Terminus and uses the name to avoid a paradox that his mother would often warn him about), who is a researcher and asks to speak to Tegan privately since she is carrying biomes and microorganisms not seen for thousands of years. Once alone, Adric reveals the truth to Tegan. Tegan, immediately realising the consequences that Adric thinks it's an earlier point in time and asking for them to save his mother, creating a paradox as she will have never left Terminus in the first place. She informs the Doctor of the situation who realises the severity and proceeds to get everyone back to the TARDIS and get away as soon as possible, despite earlier being intrigued by the chronoscope and being reminded by Turlough that they'd come to investigate the strange signal picked up by the TARDIS. Angered at never being trusted, Turlough storms off to go talk to Adric. Turlough tells him the truth not knowing the severity and Adric becomes angry at his mother seemingly having left them to travel.

The Doctor tries to get Tegan and Nyssa to the TARDIS but Tegan tells Nyssa and they are then found by Sibor, who brings them back to see Adric, and leaves them alone. Adric asks to speak with Nyssa privately and reveals to her he knows and tells her about her own future, in doing so sealing Nyssa's fate and never allowing her to return to the time just after she disappeared, ensuring that the cure for Richter's syndrome she discovered is not found earlier, Lasarti, her husband, dies ten years before, alone, and Neeka becomes infected. The Doctor suspects he has told her everything behind closed doors but just then Sibor arrives with armed guards to arrest Tegan and Turlough as the chronoscope has just predicted they will commit murder by killing a watchman to make their escape and the Doctor realises the problem...

Part two
Nyssa and Adric talk about what happened over the past 25 years since she was declared dead after going missing (really ending up joining the Doctor again) and realise that they both have the other part needed to create the cure for Richter's syndrome. They prepare to create the cure but are interrupted by Mahandra who informs them that Sibor has arrested Tegan and Turlough. The Doctor, meanwhile, tries to defend them at their trial but loses and the two are locked up. Nyssa angrily confronts the Doctor and berates him for the choices he made and keeping information from her. Tegan and Turlough start to hear voices in the prison, while Nyssa, in the process of preparing a vaccine for Richter's syndrome, also hears the voices which takes the Doctor's attention away from finding a way to get Tegan and Turlough out. The cure is successful but Sibor arrives and arrests Adric, saying that she plans to use the cure they have just developed as a leverage against the Earth Empire in order to become prime designate.

The mysterious voice draws Turlough out of the prison and Tegan and Kartis (a wrongly accused convict from earlier) follow him until he finds a mysterious white cabinet in the center of the prison. Meanwhile the voice reaches out to Nyssa while she, the Doctor and Mahandra attempt to get into the prison to save Tegan and Turlough and in the meantime Adric escapes the alcazar and attempts to make contact with the Earth Empire to let them know they have found a cure. However his message gets completely scrambled into incomprehensible languages while Mahandra explains "Miracle Day" to the Doctor as they search the prison, how one day everyone on the planet suddenly woke up and were able to understand every possible language. They eventually find Tegan who has been knocked out by Turlough as he attempts to wire up the "cabinet" to give it power. Just then it sends out a telepathic field that knocks almost everyone except the Doctor unconscious and to his horror, it takes control of Tegan and Turlough and reveals itself to be the source of the chronoscope as Adric is captured by Sibor, and it reveals itself to be the Doctor's first TARDIS, his type 50 TARDIS...

Part three
The Doctor's type 50 reveals how it barely managed to escape Gallifrey and crash-landed on Valderon, where Sibor found it and realising its potential kept it trapped and used it as the chronoscope. However, it reveals that it was actually part of its plan and explains how it managed to lure the Doctor here and expresses its desire to have the Doctor return it home. The Doctor agrees but only if it releases Turlough and Tegan from its mind control which it does. He then shuts off its power and assures Turlough he'll keep the promise but would prefer to have it relieved of power.

Sibor, who has found out about what's going on, takes Nyssa and Adric hostage and finds the type 50 TARDIS, and hooks it back up to its power source from the planet's power supply but ends up getting electrocuted in the process. It then seemingly dematerialises. Nyssa finds the Doctor and explains everything and they are soon joined by Tegan and they return to the TARDIS to try track the type 50. However, it is revealed that the Tegan with them was merely the type 50 TARDIS using its still-functioning chameleon circuit to disguise itself. It then puts the TARDIS in a temporal state of grace and captures Nyssa and the Doctor. It brings Nyssa back to 3531 in an attempt to change the timeline and offers Nyssa a chance to watch her children grow up as she had missed when she began travelling with the Doctor again and was presumed dead. The Doctor tries to stop her, citing the irreparable damage she will cause to the timeline but she cannot restrain herself and departs. The Type 50 then "eats" the Doctor's TARDIS's dematerialisation circuit and leaves, stranding the Doctor. Meanwhile, the real Tegan finds Turlough and Adric and they go to find the Doctor, who explains the events that had just transpired. He explains that they have to stop the type 50 as it has now created two timelines and the results will be an explosion that could wipe out half the galaxy....

Part four
The type 50 materialises in front of Katris and Mahandra and takes on the form of the deceased Sibor and takes over their minds. Inside the TARDIS, the Doctor has Adric reach out to his mother in the past which is now altering the future using the TARDIS telepathic circuits to convince her not to go inside, and after finally getting through to her, manages to convince her to fly off-world to somewhere far-away and distant and have no contact with any of them for the next 25 years. The Doctor explains that this will stop the new timeline being created and stop the blinovitch limitation effect which the type 50 is using as an energy source to rebuild itself. The timeline stabilizes and they are able to finally exit the TARDIS without being destroyed by the effects which had hindered their earlier attempts to escape, and find Nyssa arriving on a shuttle, having had to wait out the 25 years alone and due to this has become bitter and resentful, especially of the Doctor.

They then confront the type 50 but discover that there is a paradox still keeping it alive: moments earlier, Nyssa had revealed to the Doctor that Galen is really Adric, her son and that she was contacted by the Doctor before he regenerated, and when she told him then she was a mother, he was extremely surprised, seemingly unaware, something from his future he should not have known about. The Doctor, however, realises a loophole: since Nyssa wasn't aware whether he actually really knew and was acting surprised, or really wasn't aware, he can do his best to feign surprise and still keep the timeline intact. The paradox resolved, the type 50 collapses, out of power and seeing nothing but its own demise. After talking with the Doctor, it has a change of heart and using its final power it helps the Doctor erase the 25 years Nyssa had to wait, partially re-setting the timeline, and the type 50 destroys itself, taking the paradox with it while a saddened Doctor and Nyssa watch on. Those possessed by the type 50 who were knocked unconscious slowly come to as well.

They regroup with Tegan, Turlough and Adric and explain what happened. They prepare to leave and Nyssa promises Adric that she'll return to see him soon after he offers to take her to see Neeka, who he is on his way to cure with their newly developed cure to Richter's syndrome. Nyssa declines but makes him a promise to come see him again, and they agree to meet on Valderon in one month's time. She then enters the TARDIS, and asks the Doctor to take her to Valderon, one month in the future and they set off.

Adric reveals that despite the promise, it was the last time he ever saw his mother.

Continuity

 * The Doctor jokes about not being able to get the dematerialisation circuit to work for years. (TV: An Unearthly Child et al.)
 * When Turlough mentions the blinovitch limitation effect, Tegan asks like having the two different Brigadiers. This happened during the events of TV: Mawdryn Undead. The Doctor also met an alternate timeline version of the Brigadier during his third incarnation. (TV: Inferno)
 * The Doctor has Adric use the TARDIS's telepathic circuit s to reach and communicate with his mother in 3531 to stop her from changing history. He had Clara use them to help them find Danny Pink after he died. (TV: Dark Water) They also interfered with the Uknown Warrior's funeral and Frances in the 20th century. (TV: The Mouthless Dead)
 * When Turlough offers the Doctor his gun, the Doctor refuses, citing "he never carries guns". The Fifth Doctor earlier tricked a guard by putting a pipe on his back into thinking he had a gun when he didn't. However, the Fifth Doctor has been known to use weapons on some occasions. (TV: Earthshock et al. )

Part one
The TARDIS is going out of control as the Doctor, Tegan, Nyssa and Turlough pursue Pik Solus who has stolen the TARDIS's interface stabiliser and track him down to Isenfel where they are forced to land and go off in search of help when the TARDIS falls through the ice and becomes irretrievable. They are found and rescued by Inger who takes them back to her mother's castle. Nyssa mentions to the Doctor that she dropped the interface stabiliser while they were being chased by some wolf-like creatures earlier. They are then introduced to Queen Karlina (Inger's mother) who is interested in the Doctor claiming to be a man of 'learning'. The Doctor seems more interested in the fact that they are not the first arrivals as the queen mentioned that someone else had arrived just some time before. Karlina in the meantime consults Balancer Skaarsgard who informs her that the equilibrium has been upset and is awaiting readings from his machines.

Balancer Skaarsgar then consults Jesper, who had seen the visitors, for his opinion. Turlough wanders the castle and is found by Inger who attempts to court him by inviting him to a night hunt, which he politely declines. Inger teases him that he will succumb eventually. Tegan and Nyssa are lead to their quarters when Tegan claims she hears something roaming the caslte but is assured not to worry. They are prompty summoned to the feast being held in their honour. The Doctor and Karlina converse when they are joined by the pair and the Doctor inquires more about the proceedings of Isenfel and the stranger that was found, whom he correctly guesses to be Solus and discovers that Solus did not survive the crash. The Doctor asks about the interface stabilizers but recieves no confirmation of its finding.

The Balancer arrives and Karlina explains that it is time for maintaining equilibrium, and since four strangers have arrived, they must execute four of their own, but the Doctor tries to intervene...

Part two
The Doctor interrupts the process saying they cannot murder for the sake of "balance" and the Queen postpones the execution for a while yet while the Doctor tries to find another way. Tegan is distraught about how the servants were willing to discard their life for the sake of balance and while Nyssa tries to explain to her that it may be their tradition and it's not their place to change it, they go off to find out what is going on at Tegan's behest. The Doctor gets a reluctant Turlough to go hunting with Inger to keep her distracted while he figures out a way to change their fundamental societal belief. Karlina consults Balancer Skaarsgar who is worried that the machine now reads "re-calibrating" which he has never seen before. She reminisces over her deceased husband and Balancer Skaarsgard accuses her of clinging tightly to the stranger in hopes he may explain what the machine does and the underlying science, something that greatly disturbs and upsets the Balancer. Turlough spots black snow which Inger explains is Isenfel's way of restoring balance if they themselves do not, claiming it is the peasants own fault to a disturbed Turlough.

Karlina takes the Doctor to the balancing room and explains to him that Isenfel always has the same number of people, animals, crops, etc and they keep meticulous count or else the planet does the job for them. The Doctor then finds out that Solus was put to death because Karlina found no reason to sacrifice a healthy subject for the sake of a sick and injured one. The Doctor is utterly disgusted and begins messing with the machine much to the Balancer Skaarsgar's chagrin, while Turlough and Inger encounter strange black beasts of colour similar to the snow they saw earlier, however, Inger does not recognise them and they attempt to flee. The Doctor inquires who was the Balancer before Skaarsgar but discovers it has always been Skaarsgard and manages to return him to his true form and takes his key, finding out that the machine controlling equilibrium is far more advanced than he thought. Tegan and Nyssa discover children in the castle and discover that Jesper and Romy have been hiding them because they believe the royals have always been shielded from the balancing so they hide them in the castle so that the families do not have to suffer by being executed to make room for the children. However, they are trapped and about to be killed by Jesper. Turlough and Inger are trapped by the beasts and while Inger embraces death as a royal, Turlough panics as there is nowhere else to go...

Part three
The Doctor and Karlina arrive in time to stop Jesper but the queen is taken aback at discovering the children, while the Doctor explains he has re-calibrated the machine to compensate for a new energy level (apparently it killed off life-forms in order to maintain a constant balance of energy on Isenfel) and they found them using the machine's map of all life-forms on the planet. The creatures pursuing Turlough and Jesper are suddenly absorbed back into the energy field and the two hurry back to the castle to explain what they saw. Tegan and Nyssa feed the children and Romy explains to them the way Isenfel works. Nyssa is asked to join the Doctor, leaving Tegan to talk with Romy some more. Skaarsgard is brought back online by the Doctor but bemoans the people he condemned to death, however, the Doctor assures him that it wasn't his fault and that if he hadn't done what eh did, everyone would have died. Nyssa arrives and the Doctor explains that Isenfel he suspects is an experiment that had been abandaoned and the inhabitants like lab rats. He instructs Nyssa to work on the re-calibration while he goes to comfort Skaarsgard and when Nyssa reminds him about the TARDIS he says he has a shrewd suspicion that it was what is causing the disturbance due to its power and that he hasn't forgotten. The Doctor finds Karlina and asks for Skaarsgard who has gone to rest. The Doctor then asks Karlina to take a team to recover his TARDIS from under the ice which she obliges but Skaarsgard arrives and offers to help the Doctor find the object he is seeking as the Doctor asked earlier, but only when the Doctor has explained to him what he is. Nyssa and Karlina go to find the TARDIS while Turlough and Inger discover the energy barrier and attempt to get back to the palace while Jesper, Tegan and Romy spot a large storm brewing and Romy believes it is her fault for taking the children away from the castle and sacrifices herself to the brewing storm thinking it will stop the blizzard from moving. Miraculously it does stop is and Tegan stops Jesper from following and gets him back on track to save the children.

The Doctor probes Skaarsgard's systems and discovers he was modeled after the original experimenter who was performing the experiment to understand the entropy decay of their universe as they discovered that it was occurring at a rapid rate and they were looking for a way to stop or slow it. Nyssa arrives and finds the Doctor in a panic as he explains that Isenfeld was an experiment meant to put off the entropic collapse, however, by raising the energy threshold he has triggered the inevitable and caused Isenfeld to collapse having now registered in its system as a failure. He panics as he has essentially condemned the people of Isenfeld to death...

Part four
Turlough and Inger continue to attempt to get back to the castle while the Doctor and Nyssa try to figure out what to do next. Tegan and Jesper attempt to find Turlough with no success but Tegan has faith he's found a way to survive but they are chased by the black creatures. Tegan and Turlough find Nyssa and Karlina who have saved the TARDIS and they try to figure out where to go as the TARDIS isn't functioning. The Doctor laments about his inability to rescue them, seemingly having condemned them but Nyssa assures him that he is good and only wanted to help as that is what he does best, having helped her and many others and says he'll figure out something. Tegan and Jesper suddenly spot a ship coming through the barrier. The Doctor reconvenes with Nyssa and Turlough, Inger and Karlina and explains he has rigged up a device that can temporarily stabilise the dimensions of the TARDIS enough-so that he can transport everyone away from Isenfel. However, Karlina is reluctant to leave and demands time to think it through. Nyssa encounters Skaarsgard again and while he is unsure about his future, Nyssa assures him that he can still learn and adapt and that he should be with his people. Karlina and Skaarsgard share an intimate moment and he convinces her to leave for the sake of her people and herself. They depart on sad but friendly terms.

Tegan and Jesper attempt to enter the spaceship but Tegan is abducted. Karlina arrives and gives her approval for her people to depart but says she will be staying and that Inger is in charge, however, the black creatures surround them and the TARDIS while the Doctor is inside installing the temporary stabiliser, when they realise that the TARDIS is the largest source of energy and attempt to breach it while its dimensions are weakened and the Doctor attempts to hold them out. Karlina, taking control of the machine, draws the creatures away while they realise that it is Skaarsgard who has given his own life to keep Isenfel aloft.

Isenfel is saved and the Doctor instructs Nyssa to make sure the balancing machine is off for good and tells Turlough to say his goodbyes. Karlina, meanwhile, prepares to be killed by the creatures but they vanish. Convinced her time is over, she continues towards the mountain's edge anyway.

Turlough says his goodbyes to Inger who reciprocates with a passionate kiss when they are interrupted by Jesper who explains that Tegan has been abducted by the spaceship they saw earlier. The Doctor and Nyssa, meanwhile, discuss moving the people of Isenfel but come to the conclusion they'd rather stay on Isenfel. They suddenly realise that amidst the chaos they'd lost track of Tegan, when Turlough arrives to inform them of the bad news.

Tegan, trapped aboard the spaceship cries out for help....

Continuity

 * Tegan says she has had practice riding horses already. (don't know where this comes from)
 * Nyssa mentions she is "a lot older than she looks", and Queen Karlina claims she has "old eyes" like the Doctor. Nyssa looks younger thanks to being rejuvenated in India in the 1920s. (AUDIO: The Emerald Tiger)
 * Nyssa mentions

Part one
Adric calls Neeka over the intercom to check up on her when he hears the TARDIS arrive and upon encountering the Doctor, learns that his mother Nyssa is gone forever, lost beyond the reach of the TARDIS in E-Space. Adric demands the Doctor explain what happened and why she will never return.

The Doctor, Nyssa and Turlough are chasing after Tegan who has been kidnapped by some space pirates from Isenfel. They crash-land on Apollyon where the TARDIS begins to lose power and they go out to explore and potentially find Tegan. They find a shanty town where they learn that the planet has no power and are celebrating "the end", saying that the stars are slowly going out and the end of the universe is closing in on them. Suddenly they spot a spaceship and suspecting Tegan to be aboard, chase after it. They see Tegan taken from the ship and follow her and her captors, Captain Branarack and his henchman. After bribing the robot guard, the Doctor, Turlough and Nyssa manage to enter and talk to Cherryanne, who explains that their friend is a tribute meant to be sacrificed and never to be seen again. They manage to free Cherryanne who explains how she and her brother ended up on Apollyon. The guard detects her escape and the Doctor distracts it to let her and Nyssa escape, while the Doctor requests the robot guard take him and Turlough to meet whoever is in charge. They are brought face-to-face with Pallister, a science tech who has created a laboratory entirely without power. He explains to an inquiring Turlough he is attempting to open a CVE and takes them to see the portal. He then gives Captain Branarack permission to pass through the portal, explaining that a "tribute" is required to provide energy from their molecular bonds almost like a human battery to power and stabilise the portal, allowing people to pass through it to N-Space. The Doctor, Turlough and Tegan are briefly reunited before Tegan is taken and seemingly sacrificed to allow Branarack's ship to pass through the portal to N-Space...

Part two
Tegan exits the TARDIS in the present and greets Adric while the Doctor explains to him that she and Turlough had been put into an induced sleep, then goes to check on Turlough and leaves Tegan to tell him what happened next.

Pallister's machine shuts down and the portal begins to destabilise, and they suspect the Doctor of sabotage. However, he makes a bargain saying he will help them discover what happened in exchange for Tegan's release. Pallister agrees. They descend but Tegan is then saved by a disguised Cherryanne in large armor and reunited with Nyssa, who created a temporary distraction. Tegan updates Nyssa on the Doctor's situation and the three of them decide it best to get away for now. Cherryanne takes them to her hideout where she had been taking care of her sick brother Raldarin. Cherryanne explains that he has the entropy plague, and warns them that they cannot touch him, saying that it may be transferred. Nyssa explains that the CVE must be sucking the energy out of this system and notes how disease seems to cause people to take drastically dangerous actions like Pallister operating such a dangerous portal. She attempts to devise a plan to help the sick and the next day she and Tegan go to the market where she pawns off her last possession of Traken, a comb, in exchange for some food. However, for a few seconds they notice that organic decay is accelerated due to the use of the portal, and the food goes bad and they are unable to return it.

Just then they spot the Doctor and Pallister in a local tent and go over to talk with him. She demands an explanation from him and he reluctantly explains that Pallister is the only one who will be able to get them back to N-Space and hence his attempts to get "chummy" with him. Despite them reminding him that Pallister kills people to do it, the Doctor claims that E-Space is dying anyway and this seems to be their only chance and he can't always save everyone. The two reject this but he begs them to go back to the TARDIS and gives them the key, demanding they stay put until all this is over. He then hurries away. Tegan and Nyssa return to Cherryanne but they spot the sentinels and want to give themselves up to avoid Cherryanne putting herself in danger for their sake, however, she refuses and hides them despite their protests. When the sentinels leave after warning Cherryanne, Nyssa says she and Tegan will go back to the TARDIS to get food and medicine. However, they can't find the TARDIS, noticing it has been dragged to Pallister's citadel and decide to try find it but they hear people running away crying that the Sandmen are coming. Nyssa and Tegan attempt to escape them as they watch the Sandmen drain people's energy, killing them and leaving them as a pile of dust. They try to enter the citadel but the robot guard denies them access as it also denies access to the pleading citizens attempting to escape the Sandmen, deeming that they are too unhealthy, badly effected by entropy plague. The two manage to get away but are found by Cherryanne and they return back to her hiding place... only to find out that Raldarin has been turned into a Sandman as well...

Part three
Tegan, experiencing residual effects, becomes very tired and the Doctor helps her back into the TARDIS to rest and leaves a newly awakened Turlough to explain the rest.

He explains that The Doctor attempts to find the problem with Pallister's machine after he, Turlough and Pallister go to see the problem and fixes it, but when they return they find Tegan has escaped. The Doctor convinces Pallister that they didn't sabotage him nor help Tegan escape and while he reluctantly accepts, they are attacked by Captain Branarack who is furious at being unable to pass through the portal. They take Turlough as a tribute instead despite the Doctor's protest in order for Pallister to demonstrate to Captain Branarack that the machine works. They all suffer entropic acceleration, and when Branarack attempts mutiny Pallister has his sentinels easily subdue him. Pallister has them locked up and wants the Doctor's help while Turlough faints, an after-effect of the induction chamber.

Turlough awakens and the Doctor tells him what he's been up to, including seeing Tegan and Nyssa and instructing them to hide in the TARDIS and explains that they need to close the CVE and by closing it E-Space will stop its immediate decay and have a few centuries left to give the inhabitants time to live out their natural lives so that no one has to die. He then tells Turlough that he will be sacrificing himself to send him, Nyssa and Tegan through the portal back to the safety of N-Space and will close the portal from this side, trapping himself in E-Space, despite Turlough's protests, also saying he has tricked Pallister. They are interrupted by Pallister who has had the TARDIS brought back at the Doctor's "request" (claiming it will help his machine with the CVE) and they discover that Nyssa and Tegan didn't listen to him as they are not inside the TARDIS and he guesses that they are with Cherryanne, and he asks some sentinels be sent out to find them. They follow Pallister to the holding cells which are crowded by people and hear Captain Branarack demand to be let out as one of his men has already caught the entropy plague. Pallister panics and has his remaining sentinels that have not been effected by the entropy drive all the prisoners, those effected by entropy plague and those not, out of the settlement. The Doctor warns him that this will only spread the plague faster but Pallister is adamant and refuses. Just then a sentinel informs them that people are attempting to get inside the citadel due to the outbreak of Sandmen caused by Pallister ordering the release. The Doctor convinces Pallister to close the portal to stop the entropy decay but only after Pallister himself and Turlough, Nyssa, Tegan and Cherryanne have passed through onboard Captain Branarack's ship, the Buccaneer. Tegan, Nyssa and Cherryanne are brought to them by the sentinels and the Doctor explains his plan, but they protest and Nyssa and the Doctor argue as Nyssa demands that he let her stay behind in his place since she can do the most good to help Apollyon recover once the portal is closed and things return to some semblance of normal...

Part four
The Doctor then gets in a heated argument with Turlough who says that they can sacrifice Captain Branarack and his crew instead, as he claims that their lives were less valuable which disgusts the Doctor. However, it is too late as Captain Branarack and his remaining crew find them and take them hostage, having overheard their situation. They decide to sacrifice Cherryanne for use in the induction chamber as revenge against the Doctor, to make him suffer, and force Pallister to give uncountermandable orders to his sentinels to kill anyone that tries to get in their way and thwart their plan. Captain Branarack brings Pallister onboard and has the sentinels prepare for their departure, leaving the Doctor, Nyssa, Turlough and Tegan to be trapped in E-Space. Just then the Sandmen, having managed to breach the citadel, descend upon the ship, destroying the sentinels in the process while Raldarin, in a last act of conscience, manages to stop the induction chamber from killing Cherryanne before losing the rest of his mind. The portal is forced open into a permanent state and Cherryanne sacrifices herself to stabilize it much to the parties regret. Thinking quickly, the Doctor manages to order the sentinels to get the TARDIS aboard the now nearly-destroyed Buccaneer, the entropy field having vaporized Branarack, Palliser and the crew before-hand. They reluctantly leave Cherryanne to seal the portal after she volunteers herself as a sacrifice to close it once they all get safely back to N-Space, however, they notice that the portal is still unstable. The Doctor realises he must go back and sacrifice himself to stabilise and close the portal, however when he attempts to leave the ship, he finds the door locked and sealed, and to his horror, realises that they have been locked in by Nyssa. They manage to contact her and the Doctor tries to persuade her to let him take her place, explaining that once sealed she will never be able to escape and they will never be able to come back for her. However, it is too late and the ship passes through the portal, leaving Nyssa behind and returning the Doctor, Tegan and Turlough to N-Space.

The Doctor then finishes the story, explaining to Adric that once they arrived back in N-Space, the TARDIS returned to life and Tegan and Turlough collapsed, effected by the residual effects after which the Doctor had put them to sleep to help them recover. He suspects that Nyssa is still alive even after using herself in the induction chamber to close the portal but they are unsure. Adric angrily tells the Doctor to leave, berating him for not doing anything to save his mother despite the Doctor's attempts to insure him that he did his best and didn't want this outcome either.

Nyssa recounts what happened to her after the portal closed in a letter addressed to Adric, how she helped the people of Apollyon through their sickness and recover and how in her final days she tends a garden as she has taught the people of Apollyon everything she can and she is close to death. She expresses her thoughts, her love and her sorrows to Adric in the letter despite knowing full-well it will never reach him, explaining that she wanted to put her thoughts down before passing away but notes that a new star, never-before seen, was spotted in the sky a few nights ago, prompting her to claim that there may be a future yet for the universe of E-Space.

Continuity

 * The Doctor mentions they yhave been tracking Tegan since they left Isenfel. (AUDIO: Equilibrium)
 * The Doctor tries the TARDIS crank handle. (TV: Day of the Daleks et al)
 * Turlough jokes that it's been a while since someone has called him "boy" after being referred to as such by Captain Branarack. The Black Guardian used to refer to Turlough by this monicker. (TV: Mawdryn Undead et al.)
 * The Sandmen whsiper "Ashes to ashes, dust to dust", a line used often by other charcters. The Seventh Doctor muttered this after driving the Renegade Supreme Dalek to destroy itself. (TV: Remembrance of the Daleks)