Planet of the Spiders (TV story)

Planet of the Spiders was the fifth and final serial of season 11 of Doctor Who. It was the final regular appearance of Jon Pertwee as the Third Doctor and introduced Tom Baker as the Fourth Doctor in the final moments of part six. This was also Richard Franklin's final appearance as Mike Yates, outside of cameos.

The story was the first to use the term regeneration to describe the biological process that caused Time Lords to change in physical appearance and introduced one of the Doctor's mentors, K'anpo Rimpoche, as a means to further explain the mechanic and cement it into the Doctor Who mythos.

Counting K'anpo's regeneration along with the Third Doctor's, this is one of two of the Doctor's regeneration stories (the other being Twice Upon a Time) to feature a case of double regenerations and the only televised story where more than one Time Lord regenerates.

Synopsis
The blue crystal that the Doctor took from Metebelis III in a previous adventure is desperately sought by the Eight Legs, a race of mutated spiders, as the final element in their plan for universal domination. With help from an old mentor, the Doctor realises the only way to foil the plot is to make the ultimate sacrifice. The Doctor must risk death to return to the cave of the Great One and save the universe.

Part one
In the English countryside, Mike Yates, discharged from UNIT and recuperating at a rural Buddhist meditation centre, is having a casual stroll when he hears a strange sound coming from the cellar. He secretly peers in and sees five men — Barnes, Land, Keaver, Moss and their leader Lupton — conducting some kind of unusual meditation. He sees a strange glow appear on the mandala they are all sitting around, and as he moves closer, he gets caught in a spider's web and unintentionally knocks a candle over but is able to run away before the group see him.

Meanwhile, the Doctor is researching psychic energy, enlisting the Brigadier to accompany him to a theatre show to see Professor Herbert Clegg, a clairvoyant.

Barnes asks Lupton if they should carry on but he says it's too late. Lupton is curious that none of them saw anything, but Barnes believes it was the wind as the door was left open. They then hear a car start up. Lupton knows there is only one person at the meditation centre who owns a car: Yates.

The Doctor asks Clegg back to UNIT HQ. Clegg believes they want to hire him to perform his act, but the Doctor informs him about the experiments he's conducting and tells the Professor he would like his help. Clegg admits he isn't actually a professor at all; it's merely for "professional purposes". The Brigadier then interprets this as an indication that Clegg's act is all just trickery to which he confirms is true and asks that they not tell anyone. The Doctor reassures Clegg that his secret is safe: the secret that Clegg himself is actually a gifted psychic. Clegg is dumbfounded as to why the Doctor would jump to such a conclusion. He tells him that he was able to work it out as, during his act, he made some mistakes; he answered some questions before his assistant had even said anything. Clegg silently curses himself and admits that his gift is constantly growing stronger and that he doesn't want it. The Doctor asks him if he would give them a demonstration. He then successfully levitates a tea tray using the power of his mind, but is unable to hold it for long and drops it. The Brigadier suggests he do that in his act, but Clegg retorts that it would send him mad. The Doctor assures him that his gift may seem special but such powers lie dormant in everyone. Clegg is sceptical of this, but the Doctor further assures him that he can use his research to find out why the power has developed more in Clegg than anyone else. Clegg agrees to help.

Lupton is telling the monk Cho Je that a female journalist is coming to the meditation centre and says that they don't want her there. Cho Je remarks that they cannot completely shut out the outside world, but Lupton retorts that doing so is exactly what the monk did when he was in Tibet. Cho Je says that these views pass in time and that Lupton will learn this through his meditation. Lupton argues that he and the others came to the meditation centre to get away from others and find solitude. Cho Je replies "one day you will learn to walk in solitude amidst the traffic of the world" but Lupton still maintains that the journalist should not come. Cho Je replies that Yates has gone to pick her up from the station.

Sarah meets Yates at the train station and gets into his car before asking him what's going on. He then drives off.

Lupton knows that Yates is bringing Sarah because he saw them meditating and suspects something. Barnes suggests they stop for the time-being but Lupton replies that they're "on the point of breakthrough". Their conversation is then interrupted by the simple minded handyman Tommy, who shows them a "pretty flower" — a daisy. Barnes tells Tommy to carry on with his work, but he answers that he's finished weeding so Barnes tells him to find something else to do. Tommy promptly grabs Barnes's arm and asks the men if they'd like a cup of tea. Barnes then roughly pushes Tommy, causing him to fall over, and they leave. Tommy is upset when he finds the flower has been squashed in the fall, and begins to cry.

While travelling to the meditation centre, Yates has told Sarah the basics of what's happening and that it would be a good story for her magazine but she is a bit sceptical and wants to know more; specifically why Yates is at the meditation centre anyway. He replies that, following the 'Golden Age mess', he wanted to sort himself out and, after hearing what meditation can do for the soul, decided to try it.

Meanwhile, the group have started meditating again.

Sarah says that it doesn't sound like anything strange is happening but Yates is still convinced and says he believes it's a matter for UNIT. Sarah suggests he simply tell the Brigadier or the Doctor but he replies that they wouldn't believe him after what happened last time he saw them. Sarah then realises he wants her to have a look and then tell the Brigadier for him to which she agrees as long as he can convince her. A tractor then suddenly appears in front of them and Yates swerves violently off the road to avoid it. Once the car has stopped, they look around and realise the tractor has disappeared. Sarah admits she's convinced. Back at UNIT, the Doctor has wired Clegg up to an electroencephalograph which can monitor his brainwaves. As a test, the Brigadier then gives Clegg his watch who is able to tell him the full history behind it and the Brigadier, rather brusquely, confirms it's all true and remarks that the Doctor should have enough from that test; but the Doctor answers they may have too much. He then introduces an IRIS machine which can turn Clegg's thoughts into pictures. He gives him the sonic screwdriver and the machine produces images of when the Doctor previously used it against the Drashigs.

Sarah is interviewing Cho Je who is explaining the various teachings provided at the meditation centre and what men can gain from them. Cho Je then excuses himself for a meditation class but Yates asks that, if used wrongly, whether meditation could be dangerous. Cho Je confirms that it could but believes that it would never happen there.

Clegg believes he was losing mind after seeing such "fantasies" but the Doctor and the Brigadier assure him he's doing well. Benton then walks in with a package that has arrived from South America and the Doctor works out that it must be from his former assistant Jo Grant (now Jo Jones). Before opening it, he gives it to Clegg and asks him what's inside. He replies that it has come from beyond the stars and eventually says that it is "a gemstone; a blue jewel". The Doctor and the Brigadier realise it's the Metebelis crystal the Doctor gave Jo as a wedding present. He opens the package and, sure enough, the crystal is inside.

Yates has finished showing Sarah around the centre, but she insists on sneaking a look at the meditation class. They peer in through the door — which bears a sign reading MEDITATION ROOM / PLEASE BE QUIET — and see multiple people, including some from Lupton's group, sitting down with their eyes closed while a soundtrack of men chanting is playing which Yates says helps with the meditation. They quietly close the door and are greeted by Lupton and Barnes. Yates introduces her and Lupton remarks that Cho Je told him she was coming. He asks whether she's had an informative visit and she confirms she has but remarks she had a bad start. She initially begins to tell them what happened to them on the road but Yates promptly cuts her off and says they had an accident where their car ran off the road. Lupton remarks that the roads are dangerous and they should be more careful. He asks that Sarah stay and share a meal with them, or at least a cup of tea. Sarah would love to, but Yates insists that she has to leave or she will miss her train. Sarah says she has hours yet, but Yates remarks she must have misread the timetable and drags her off. She's furious that, after all the fuss he made about this, he's now taking her away. Lupton watches them leave and believes they won't have any more troubles, seeing how scared Yates was, and tells Barnes they will carry on as usual.

Yates then tells Sarah the man she spoke to was Lupton; thus making her realise why Yates ended their conversation so abruptly. Yates deduces that, from what Lupton told them, he and the group tried to kill them by manifesting the hallucination of the tractor. They pull up a short distance from the centre and Sarah asks why they're running away. He tells them that they're not and that he only wants Lupton to think that they're leaving. They then climb over the wall.

The Doctor is reading Jo's letter. She says that they still haven't found their toadstool and believes that they won't until they get rid of the crystal as some people they've met believe it's bad magic. Unseen, Clegg then picks the crystal up and curiously examines it.

Sarah and Yates climb through a window to get back into the centre, but they are spotted by a curious Tommy. They tell him they're playing a game and he initially wants to play as well, but Sarah tells him it's a game where he has to keep it a secret. Tommy, who is enthralled by shiny objects, notes Sarah's "pretty" brooch; she then gives it to him and he walks off happily. They sneak into the cellar and hide. The group come down shortly afterwards and start meditating again.

The Doctor finishes reading Jo's letter when the crystal starts glowing and the room begins to violently shake. The Doctor is able to stop it by wrenching the crystal free from Clegg's grasp, who then screams and slumps in his chair. The Brigadier says he'll get the medical officer, but the Doctor tells him it's too late: Clegg is dead.

Sarah and Yates watch as the group continue meditating and summon a giant spider into existence...

Part two
The men are alarmed at the sight of the giant spider. Keaver tries to run, but is blasted by it. Lupton commands it to leave, but it tells him that it has come to give him the power he seeks. It orders him to turn around where it promptly jumps onto his back and disappears.

Back at UNIT, the Brigadier is curious as to how Clegg died. He wonders if it was the crystal, but the Doctor doesn’t see how it could have been and decides to check the IRIS machine to see if it recorded Clegg’s thoughts before he died. It reveals that he saw visions of spiders.

Lupton orders the men to go back to their rooms and not tell anyone about what happened. Barnes is curious about whether Lupton is alright but he replies that he’s never felt better.

The Doctor decides that he should look into the crystal himself. Benton offers to do it first as the Doctor is not expendable; he replies that he’s already responsible for one man’s death but thanks Benton anyway.

Sarah sneaks back out of the window, but Yates decides to stay behind so as to not arouse suspicion. Barnes is wondering where the spider has gone, but Lupton tells him that it is still on his back; it has joined their minds and he can hear it speak if he concentrates. He sends Barnes away and the spider then tells him it can sense the crystal which is the reason it has come to Earth. It tells him to concentrate and he says “I can see a man staring into a blue light; the light of a crystal.”

The Doctor has seemingly gone into a trance staring at the crystal. He then comes around once Benton places a mug of coffee in front of him. He reveals the only thing he could see in the crystal was the face of his old teacher; the person who first taught the Doctor how to see into his mind when he was younger.

Yates wants to speak to the Abbot of the meditation centre K'anpo Rimpoche about what he’s seen, but Tommy tells him to go to bed. Yates gives Tommy his necklace to try and distract him, but he merely repeats himself before wandering off. Lupton then appears and repeats Tommy’s instructions.

Sarah is trying to tell the Doctor about what she and Yates saw at the meditation centre but he’s too busy focusing on the crystal and isn’t fully paying attention. However once she mentions the word ‘spider’ he instantly stops and demands that she repeat the story from the beginning.

Lupton arrives at UNIT looking for the Doctor and a guard directs him on where to go but asks to see his pass. He then fires a blast from his fingers at the guard, incapacitating him. The Doctor explains to Sarah how he got the crystal on Metebelis III and of the possibilities of its power. Sarah speculates that the giant spiders want the crystal back, but the Doctor says there aren’t any giant spiders on Metebelis III. Lupton then incapacitates Benton and spots the crystal in the lab; the spider tells him to concentrate. The crystal then vanishes and reappears in Lupton’s hand.

He then tries to escape by stealing the Whomobile. The Brigadier, Benton and Sarah give chase in Bessie while the Doctor uses a gyrocopter. They soon speed past a police car which promptly begins pursuing them. Lupton eventually stops at an airstrip and hides nearby. The Doctor and the others discuss what to do and the policeman tries to get them to explain why they were speeding but the Brigadier simply shrugs him off. Lupton then steals the gyrocopter and the Doctor and Sarah use the Whomobile’s flying ability to continue the chase; the Brigadier and Benton then return to UNIT, leaving the policeman utterly bemused.

Lupton is forced to land the gyrocopter due to lack of fuel and steals a speedboat. The Doctor then steals a hovercraft and cuts across the land to catch up to him (unintentionally running over a tramp in the process). The spider then says that it will get help from Metebelis III and tells Lupton to concentrate. The Doctor finally manages to board the speedboat — only to discover Lupton has vanished…

Part three
Lupton re-appears at the meditation centre just as Cho Je walks past and greets him. However, his arrival was secretly observed by Tommy, who notes the "pretty" crystal. Going back to his room, Lupton reflects on their success, though exhausted following the chase. The spider then connects his mind to Metebelis III where he sees a room full of other giant spiders (who call themselves "Eight Legs"); one being the Queen who orders them to return the crystal. Lupton is surprised that he is being seemingly forgotten even though he played a key role in getting the crystal. The Queen is convinced to let Lupton continue to serve them so as to aid them in the Great One's true plan: the conquest of Earth.

The spider leaves Lupton to sleep and detaches from his body.

The Doctor, Sarah and Yates are speaking to Cho Je about what has happened, but he does not believe Lupton could be involved, remarking that he saw Lupton at the time they claim that they were pursuing him. Barnes overhears this conversation and then goes to speak to Lupton about it. Upon seeing the crystal, Barnes realises they were telling the truth and tries to convince Lupton to abandon what he’s doing. However, Lupton reflects on his past and says this is the perfect chance for him to get power — which is why he came to the meditation centre in the first place. While they are talking, Tommy secretly leans in through the window and takes the crystal. He then goes to a cupboard under the stairs where he often seeks solitude, and adds it to his collection of "pretties", which he keeps in a shoebox.

The spider then re-appears and tells Lupton that Cho Je will want him to speak to the Doctor and also tells him to send Barnes away. Lupton refuses to talk to the Doctor but the spider inflicts unbearable pain on his mind to force him to comply. Lupton then discovers he can inflict the same pain on the spider, due to their minds being connected. The spider relents and says they will go to Metebelis III, but Lupton is unwilling to just become the Queen’s slave. The spider tells him that they can work together to make sure they both obtain power and then jumps onto his back again. They then discover the crystal is missing.

While the Doctor and Yates are still talking to Cho Je, Tommy appears; Sarah goes to talk to him and he tells her that he as a present for her. The Doctor is still anxious to see Lupton so Cho Je sends Moss to fetch him. Lupton initially suspects Barnes of taking the crystal, but he says he would have no reason to; he then questions whether it’s on Metebelis III but the spider says her sisters don’t have the power to transport it there. Lupton decides they will have to bluff the Queen and say they still have the crystal.

While Sarah is waiting for Tommy to get her present, she spots Lupton and Barnes talking. Moss then appears, but Lupton asks him to tell the Doctor that he couldn’t find him. Lupton then goes into the cellar. Sarah then asks Tommy to tell Yates that she is following Lupton into the cellar. As she runs off, Tommy holds out her present which is actually the crystal.

Sarah hides while Lupton rolls out the mandala and begins chanting. Tommy tries to repeat Sarah’s message to Yates and he casually dismisses it, but the Doctor realises he’s trying to tell them something important. Moss then appears and says he can’t find Lupton but Tommy shouts “Lupton in the cellar! Sarah Jane Smith! In the cellar!” The Doctor asks to see the cellar and Yates shows him the way. Sarah then watches as Lupton steps onto the mandala and disappears. She does the same and finds she can’t move. The Doctor and Yates run over to Sarah, but she also disappears and finds herself on Metebelis III, where she spots Lupton in the distance. Suddenly, someone grabs her from behind.

The Doctor tells Yates that he’s going to Metebelis III after her. Yates is unsure whether the Doctor will successfully make it there due to the TARDIS being unreliable in the past. However, the Doctor says that the planet’s co-ordinates are programmed into the system, but he’ll leave the actual landing place to the TARDIS herself. Yates smiles and comments that the Doctor speaks of the TARDIS as if it was alive and he replies “Yes. Yes, I do. Don’t I?”

Sarah is brought before a group of primitive humans. The one who grabbed her, Tuar, believes she is a spy. His father, Sabor, is angry with him for endangering them all and demands that he release her. Tuar’s sister, Rega, tries asking Sarah who she is and how she came to be there, but Tuar angrily yells that they should kill her. Sarah tries to profess her innocence, but when she uses the word "spiders" everyone is shocked. Tuar is even more convinced Sarah is a spy, as only a person of this sort would use the "forbidden word". Tuar tries tries to throw Sarah off the cliff, but his brother, Arak, stops him. Their mother, Neska, asks Sarah where she’s from and Sabor becomes very intrigued when she says she’s from Earth, asking if she came in a starship “like our ancestors did”. Sarah tells them she doesn’t know how she arrived, but Tuar believes she is lying. The sound of trumpets then fills the air, indicating the Queen of the Eight Legs is coming. Neska orders Arak to hide, and he and his family, along with Sarah, run into their house.

The Queen and her guards then arrive. The Guard Captain demands that the "Two Leg" Arak ("Two Leg" is the Eight Legs' name for the humans) present himself, due to the fact that he had previously attacked a field guard and left him to die, saying that if he doesn’t, one male Two Leg will be taken from each family in his place. Arak wants to go, but Sabor suggests that he speak to the Queen as he believes she will listen to him. Sabor tries to plead with the Queen, saying that the guard was cruel and heartless, and struck Neska for no reason, which is why Arak attacked him, but she refuses to listen — demanding to know where Arak is. Sabor says he helped him escape to the hills. The Queen tells him this means he will have to take his son’s place, which he agrees to. Sarah asks what will happen and Tuar says the Eight Legs will eat him. Neska then runs over to Sabor, but one of the guards attacks her. Rega rushes to her mother, but the Queen spots Sarah and realises she’s a stranger. Sarah surrenders herself to prevent Arak being discovered.

The Doctor then arrives in the TARDIS and briefly speaks to the Queen who, upon learning that he and Sarah are from Earth, orders her guards to bring him along with Sarah. Rega gives Sarah her cloak and she slips away while the Doctor battles the guards. The Guard Captain then blasts the Doctor, incapacitating him…

Part four
The Guard Captain notices that Sarah has gone. They leave, but take Sabor with them.

At the meditation centre, Yates watches as Land, Moss and Keaver go into Barnes’s room and hang a DO NOT DISTURB sign on the door. Yates cautiously approaches the door and tries to listen.

Tuar believes the Doctor is dead but Sarah sees him moving and Tuar realises he is alive.

Yates listens as Barnes and the others try to make sense of what has happened to Lupton and what they should do when they notice the doorknob turning. Barnes slowly approaches the door, only to find Tommy’s standing on the other side doing some cleaning. Barnes believes Tommy was spying, and points to the DO NOT DISTURB sign, demanding to know "Can't you read?!" Tommy tells Barnes he’s learning to read from a book his mum gave him. Barnes promptly slams the door and Tommy tries to read the sign, but finds he can’t and decides to do some reading. Yates then emerges from his hiding place and goes back to the door.

On Metebelis III, a bell rings which indicates a curfew is now in effect; anyone caught outside after dark will be killed. The Doctor’s condition is worsening and Arak tells Sarah he is dying, but she refuses to believe it. Rega says there is no cure and that the Doctor should be dead.

The Queen arrives back at the council chamber to find Lupton and his spider sitting on her throne. She angrily demands to know who he is. The spider tells her that he is the one who helped her. The Queen orders a guard to take Lupton, but then he reminds her of the crystal. The spider falsely confirms that they have it. Lupton says they know where it is hidden but will not turn it over until they receive their rewards, shocking the council. When the spider concurs with Lupton, albeit uncertainly, the Queen then tells them that they are not aware of the extent of their failures; informing them that they were followed by “two Earth spies”. She says that the male is dead, but the female is still alive and therefore still poses a danger. She suggests to the council that, until the female has been captured, they should refuse Lupton and the spider’s demands, to which they agree.

Tommy tries reading a simple children’s book (with some difficulty), but hears a strange sound coming from the crystal and it starts glowing; Tommy then collapses. He wakes up shortly afterwards and continues reading, discovering he can now do so with ease.

Arak remarks that the Eight Legs will keep Sabor alive for a little while meaning there's a chance they could rescue him and Tuar suggests they attack. Arak admits he is afraid to do so but becomes very angered when Tuar calls him a coward. A fight very nearly starts between them but Rega breaks them up. Sarah tells them she’s certain that the Doctor could help them. He, very weakly, tells her that inside the TARDIS there is an old leather satchel that contains a device which is the only thing that can save him. Arak warns Sarah that the guards will kill her if they see her. She successfully makes it to the TARDIS and Arak admires her bravery but Tuar says she’s being foolish. She comes back out with the satchel and sets it on the ground while she locks the TARDIS but Lupton captures her. Arak manages to retrieve the satchel with Rega remarking that he’s not a coward and Tuar agrees. The Doctor asks for Sarah and they reply that she's not there but give him the device. He holds it and it begins to make a loud sound and then there’s a flash of light from his fingers. He thanks them and is already sounding stronger.

Tommy goes into the meditation centre's library and looks at one of the books, which is a collection of poetry. He finds he can read it easily, and reads aloud the opening verse of a poem, "The Tyger" by William Blake; he calls this "pretty", then corrects himself to "beautiful". Tommy then takes several more books.

Meanwhile, Sarah is thrown into a cell where Sabor has already been cocooned.

Barnes and the others are still discussing what they should do when Yates decides to knock on the door. The others hide, while Barnes quickly lies on his bed pretending to read. Yates enters and remarks that he heard them talking and thinks they should have a chat when Moss knocks him out; though Barnes, Land and Keaver are angry with him for doing so.

Dawn breaks on Metebelis III and the Doctor is fully recovered. He cheerfully wakes the others.

Sarah wakes up to find she’s also been cocooned. Sabor tells her she’s a prisoner and there’s no point in struggling. Sarah asks Sabor what will happen to them and, he remarks that the Eight Legs usually eat the sheep that they breed for them — but they prefer humans.

The Doctor praises the mutton broth that Arak made for him, curious that they have sheep there. He says that their ancestors, who the Doctor works out were colonists, brought the sheep with them. Arak explains that 433 Earth years previously, their ship came out of a time jump with no fuel left and crashed on Metebelis III. Tuar is angry that the Doctor is just sitting there chatting while Sarah is a prisoner, but he says that she’ll be alright for the time being as the spiders will want to know how she arrived. The Doctor confirms that he can help them, but needs to know how the spiders came to be on Metebelis III.

Sabor is telling the same story to Sarah and says that they also came from Earth, but Sarah says there aren’t any spiders of that size on Earth. Sabor admits that’s true, but says there were spiders on the ship that crashed and the blue crystals in the mountain gradually made them grow larger and smarter. By the time the humans discovered them it was too late.

Arak says that the spiders have brutally ruled over them ever since, controlling them through fear. They once wiped out an entire village of humans, 269 people, including children, because they were keeping too much food for themselves. The Doctor asks them to get some pebbles for him, saying that he’s “playing a hunch”.

Yates wakes up to find that his hands are tied and that he’s been gagged.

The Doctor is checking each stone against the device, remarking to Rega that the crystals can’t be the only mineral on Metebelis III with an unusual structure and that he’s trying to find a stone that can absorb the spider’s attacks. Eventually he finds a suitable one. He then sets off for the mountain, telling Arak and the others to follow him as soon as they can.

Sarah is continuing to struggle, but Sabor tells her to rest, leading her to angrily ask why he’s so calm. He replies that you’re only frightened when there’s hope of rescue, saying that they have none, but she refuses to accept it. The Doctor is wandering through the mountain when the Guard Captain spots him and tries to blast him again; the Doctor blocks the blast with the device. They briefly fight until Lupton arrives and demands that the Doctor be killed. Another guard says he has orders from the Queen to have Lupton arrested. The Captain and another guard take Lupton to the council. The Doctor tries to escape, but is promptly captured, remarking that things are getting monotonous. The guard tells him his execution has merely been postponed rather than cancelled and he is taken away. Sarah asks Sabor how long they’ve got and he says it could be a week, a few days, an hour… Sarah is thrilled when the Doctor walks in but, upon noticing he is accompanied by guards, she groans in despair.

Part five
The Queen is accusing Lupton and his spider of treason, stating that the crystal is still on Earth. Lupton asks how they found out and the Queen says they traced its vibrations through space and time, which is how they found it originally. Lupton claims that he knows where the crystal is hidden on Earth, meaning that they still need his help if they want to invade. The Queen cautions his words but the spider retorts that her arrogance is interfering with the Great One’s plans, causing some of the council members to voice their doubts about the Queen. She warns them not to make any snap decisions, saying that she will speak to the Great One herself about it.

The Doctor is now also cocooned. Sarah asks that if the spiders wanted the crystal so badly why they didn’t just take it before he did. He answers that the spiders arrived long after he left. The Doctor tells them that Arak is trying to rally members of other villages to attack the mountain, saying they can now defend themselves. The guards then arrive and cut Sarah out of her cocoon. As they’re taking her away, the Doctor tells her to try and stall them.

Neska and Rega share a tearful goodbye with Arak and the others before they set off for the mountain.

The Doctor manages to wriggle out of his cocoon using a trick Houdini taught him, and tells Sabor that once he’s rescued Sarah he’ll come back for him. Sarah is brought before the Queen who says that she wants to help, but Sarah is sceptical. The Queen says she does not agree with the council’s plan to invade Earth, believing it to be foolhardy and a big risk. She says she has lied to them about visiting the Great One and that she only desires peace with the Two Legs, intending to help Sarah and the Doctor escape back to Earth, but Sarah is curious as to why. She asks Sarah if she knows about the crystal and she states that Lupton has it, but the Queen tells her that it’s on Earth. Sarah then realises that the Queen wants them to get the crystal back for her. She asks that the Queen release Sabor and listen to the Two Legs' grievances to which she agrees. Sarah asks the Queen what she wants her to do.

Barnes un-gags Yates who then asks what they’re going to do. He replies that they can only wait for Lupton to get back and hold Yates until he does; even though they’re not sure whether he can get back. Yates suggests they re-open the bridge the way they did it the first time, but Barnes tells him they need five people to do it. Yates offers to help them, to try and also get Sarah back. Barnes agrees.

Lupton says they can return to Earth and retrieve the crystal which will therefore open the way for the invasion. The council question what to do if the Queen returns from the Great One with a different plan. Lupton’s spider says they can’t trust the Queen, but the council retorts that they can’t be trusted either. Lupton is furious that the spider is not going to use his plan, but she begins inflicting mental pain on him again until he agrees to obey.

The Doctor hears Sarah’s voice coming from a nearby cave and follows it.

Tommy is now reading very fluidly, but realises he doesn’t understand the words and decides to ask Yates if he can explain what’s happened to him. He then overhears Barnes and Yates talking about when they’ll meet in the cellar. Tommy then recalls recent events such as Lupton appearing from nowhere and Sarah saying how she’s following him into the cellar. He realises the crystal is somehow connected to it all and decides to ask Cho Je, but hides the crystal.

The Doctor continues following Sarah’s voice, but soon hears another voice warning him not to enter due to the lethal radiation within. He asks of Sarah and realises that the voice he heard was just an illusion and he is now speaking to the Great One. She orders the Doctor to return the blue crystal that he stole, revealing it is the one last great crystal of power, and then humiliates him by forcing him to march in a circle like a toy tin soldier via her psychic power. The Doctor is too overcome with fear to face her and leaves.

Barnes, Yates and the others have started meditating. The spider detects that the bridge has been opened and Lupton, realising what the group are doing, warns the council that they might be hostile towards them. The spider replies that their approach will be secret. They begin teleporting to Earth unseen by the group.

Tommy has explained everything to Cho Je who is grateful to Tommy for telling him and comments that the group are being foolish. Tommy suggests they tell K’anpo and Cho Je agrees, but only once they know what to tell him. He tells Tommy to fetch the crystal while he goes down to the cellar to see what the men are doing. Tommy remarks to Cho Je that he doesn’t seem surprised to find he’s changed. He replies “When everything is new, can anything be a surprise?”

The Doctor emerges from the cave and continues looking for Sarah.

Cho Je goes into the cellar and, horrified at what he's seeing, tells the men to stop. He berates them for going against what he taught them, but a spider then hangs from the ceiling and blasts both Cho Je and Yates just as Tommy comes in. The spiders corner Barnes and the others and Tommy runs off to tell K’anpo.

The Doctor finds Sarah back in the cell area, apparently fine. They hear Arak and the others causing a fight and she tells the Doctor they can escape. She holds his hands and they disappear, much to Sabor’s surprise, just as Arak and Tuar come in to free their father. The Doctor and Sarah find themselves back in the village. The Doctor is astonished as to how she did it and she says the Queen taught her and that it is very simple. Neska and Rega then ask what’s happening. Sarah quickly updates them and bids them farewell, seemingly in an awful rush to go. The Doctor and Sarah then leave in the TARDIS.

Barnes, Moss, Land and Keaver have all been taken over by spiders. They hide as they hear the TARDIS coming back. The Doctor and Sarah emerge to see Cho Je and Yates’s bodies. She asks if they're dead; Barnes replies that they're not, which he states is an unfortunate oversight and tries to blast them. The Doctor uses a stone to block his and the other men's attacks. Tommy then leads them out, taking a small hit himself and locks the men in the cellar. Sarah is worried about Cho Je and Yates, but the Doctor says they’ll be unconscious for a while and will therefore be safe. Sarah then notices the change in Tommy and remarks he’s like everyone else. He replies “I sincerely hope not” and takes them to see K’anpo.

The Abbot warmly welcomes them and the Doctor greets him in Tibetan, apologising for not bringing him a cotton scarf. Tommy decides to keep watch outside while the Doctor and Sarah sit down to tell K’anpo their story, but the Doctor suspects the Abbot already knows most of it. He begins to wonder if he and K’anpo have met before and continues telling him about the crystal.

Barnes and the others arrive, their spiders telling them that they can sense the crystal inside the room. Tommy refuses to let them in and briefly fights them off until Barnes shouts “Kill him!”. All four men then start blasting Tommy…

Part six
As the men emerge from the cellar, Barnes says they need to separate and find the crystal. Moss declares he doesn't want any further part in it and tries to run but his spider mentally stops him. Keaver is unsure of what they should do when Land closes his eyes and says he can see the crystal. The spiders tell the men to concentrate. They sense its presence and set off after it.

The Doctor has finished telling K'anpo his story. The Abbot suggests that maybe the spiders should be allowed to have the crystal but the Doctor says that once they have it, nothing will stop them taking over Earth; Sarah adds "or even the universe itself" to which the Doctor agrees and wishes he knew where the crystal was. K'anpo then reveals it in his hand, having been given it by Tommy. Sarah then demands that he give her the crystal and begins speaking in a different voice. The Doctor can't understand what's wrong with her and she blasts him. K'anpo tells the Doctor to see through his eyes and they spot that the Queen is on Sarah's back, which explains how she and the Doctor escaped so easily.

Barnes and the others arrive, their spiders telling them that they can sense the crystal inside the room. Tommy refuses to let them in and briefly fights them off until Barnes shouts “Kill him!” All four men then start blasting Tommy.

The Doctor and K'anpo try to get Sarah to resist against the Queen's power, but she is too strong. The Doctor gets her to focus on the crystal and the Queen tries to resist, but ultimately Sarah is freed. The Queen then falls off her back and disappears.

Tommy is surprisingly resisting the men's attacks to which Barnes comments that they're not getting anywhere. The spiders agree and decide they need more power. The men stand in a circle, put their hands together and start chanting while Tommy curiously watches.

Sarah is horrified by what she's done but the Doctor assures her that she did very well; K'anpo remarks "We are all apt to surrender ourselves to domination. Even the strongest of us." The Doctor realises K'anpo is talking about him. Sarah believes this means the Doctor has been taken over by the spiders as well but he says that K'anpo is talking about his greed. Specifically his greed for knowledge and understanding. Effectively saying that these events are all his fault; if he had never taken the crystal in the first place... He then shockingly realises where he knows K'anpo from who then remarks that the Doctor was always a little slow on the uptake. The Abbot is his former mentor whom he saw in the crystal, a fellow renegade Time Lord now enjoying peaceful life on Earth. Sarah asks if Cho Je is a Time Lord too, and K'anpo replies "In a sense. But in another sense, he doesn't exist." This leaves both Sarah and the Doctor confused. K'anpo explains that Cho Je is actually a projection, that of his own inner self.

Down in the cellar, Cho Je has woken up and manages to wake Yates. They leave the cellar.

The spiders in the council chamber are all humming and Lupton asks what's going on. His spider replies that they're sending power to their sisters on Earth. He asks about the crystal, but the spider tells him to be quiet.

K'anpo briefly meditates and tells the Doctor and Sarah that the moment he has been waiting for is approaching; the "moment of truth" for both him and the Doctor who is unsure of what he is supposed to do. K'anpo asks him what he is most afraid of and he recalls his encounter with the Great One. He asks if there's another way and K'anpo sternly replies that there isn't. The Doctor concedes and K'anpo gives him the crystal. Sarah asks the Doctor what he's going to do and he replies that he's going to give it to the Great One. Sarah reminds him of what he said about the radiation levels in the cave, but the Doctor insists he has to go.

The men have finished chanting and begin blasting Tommy again. He is initially resilient, but soon falls over. The Doctor hears the noise outside and K'anpo quickly takes his hand. Yates then jumps in front of Tommy and takes a huge blast which makes him collapse. Tommy runs over to him and this lets Barnes and the others through. Tommy quickly tries to stop the last of them, but is hit over the head. The men burst into the room and spot the Doctor holding the crystal who then retreats to the back of the room and disappears. They try to blast him, but they hit K'anpo instead who then collapses into his chair and Sarah rushes over to him. Barnes orders the men to go back to the cellar. The Doctor reappears in the cellar, quickly gets into the TARDIS and leaves just as the men enter.

He arrives back on Metebelis III and is greeted by Arak and Tuar, who say their attack was a success thanks to him. He asks for their help in reaching the cave of the Great One. Arak remarks that there is more than one way in and shows him where to go.

Tommy believes that Yates is dead, but Cho Je says that he isn't quite yet and tells him to bring Yates to K'anpo.

The Doctor discovers that Arak and Tuar have led him to the Eight Legs' council chamber — meaning their attack failed and they have now been taken over. Lupton's spider mocks the idea of a bunch of Two Legs defeating them, remarking that their minds are no stronger than those of their sheep. It asks the Doctor why he's come back; he says it's to return the crystal and shows it to them. It demands that he hand it over, but he states that he will only return it to the Great One and asks if any of the council would dare challenge him for it. Lupton remarks he would and tries to take it, but the spider mentally stops him, saying that they dare not take it. The spider concedes defeat and allows the Doctor to leave. Lupton is positively outraged that he has lost his one chance of power because of a spider; the council taking offence to his use of the forbidden word. Lupton then tries to strike the spider, but it fires a blast that kills him.

Yates is waking up and K'anpo remarks that his passion is what protected him from the spider's attacks; just as Tommy's innocence is what saved him. Yates then sits up, feeling much better. K'anpo then states that his old body has had it and dies. Sarah is shocked and Cho Je remarks "Dear friends, please don't..." before he suddenly vanishes. K'anpo then takes on Cho Je's appearance and completes his unfinished sentence: "Please don't concern yourselves. I am not dying; merely regenerating." Tommy addresses him as Cho Je, but he replies that he is K'anpo. He then laughingly asks Sarah if she'll put this in her magazine, to which she smiles.

The Doctor arrives back at the cave of the Great One. She asks if he has the crystal and he angrily replies that he wouldn't have come back if he hadn't. The Great One tells the Doctor to come forward and he then sees the Great One: an enormous spider, who desires the blue crystal to complete a crystalline web that will amplify her psychic power to infinity. The Great One admits that she does not care for her subjects plan to invade Earth; knowing that one planet is nothing when her full power will allow her to take over the entire universe. The Doctor knows that such power cannot be contained and will destroy her, but she is too drunk on the thought of being the most powerful being in the universe and refuses to listen to him. She uses her psychic powers to move the crystal from the Doctor's hand to the crystalline web above her. With the crystal in place, the Great One briefly succeeds, before the web overloads (proving the Doctor right) and destroys both her and the Eight Legs. This also frees all the humans possessed by them, both on Metebelis III and Earth. The Doctor receives a lethal dose of radiation from the cave and barely manages to escape to the TARDIS. The mountain then explodes.

Three weeks later, Sarah goes to UNIT HQ, but isn't entirely sure why she's gone there but the Brigadier knows it's to check to see if there's any news of the Doctor. The Brigadier is optimistic, remarking that this is not the first time the Doctor has been gone for a prolonged period of time, though Sarah is certain that they will never see him again. At that moment, the TARDIS materialises in front of them. The Doctor stumbles out, a weary look on his face, and manages a warm, albeit weak, smile as Sarah runs up to greet him. He explains to her that he got lost in the Time Vortex, but the TARDIS brought him home. The Doctor tries to take a step forward, but promptly collapses onto the floor. The Brigadier and Sarah quickly run to his side. Sarah asks the Doctor why he had to go back to Metebelis III, and he admits he went back because he had to face his fear; it was more important for him to do so than to just go on living. As Sarah tearfully begs him not to die, the Doctor cups his hand up to her cheek and softly says, "A tear, Sarah Jane? Now, don't cry. While there's life, there's..." The Doctor cannot finish the quote before he expires.

As Sarah closes the Doctor's eyes and weeps, a projected image of the regenerated K'anpo appears and assures Sarah and the Brigadier that the Doctor is not dead and he will regenerate and become a new man. They ask when the process will begin; K'anpo replies that "There is no time like the present" and gives the Doctor's cells a little "push" to start the regeneration. He then vanishes, telling them "Look after him." The Brigadier then quickly tries to get more information from K'anpo, only to find he's addressing thin air, but Sarah exclaims, "Look, Brigadier, look! I think it's starting!" The Brigadier raises an eyebrow and says "Well... here we go again." The face of the Third Doctor fades away and reforms into that of a younger man, with long, curly brown hair. The Fourth Doctor has arrived...

Cast

 * Doctor Who - Jon Pertwee
 * Sarah Jane Smith - Elisabeth Sladen
 * Brigadier Lethbridge-Stewart - Nicholas Courtney
 * Mike Yates - Richard Franklin
 * Sergeant Benton - John Levene
 * Professor Clegg - Cyril Shaps
 * Lupton - John Dearth
 * Barnes - Christopher Burgess
 * Moss - Terence Lodge
 * Land - Carl Forgione
 * Keaver - Andrew Staines
 * Cho Je - Kevin Lindsay
 * Tommy - John Kane
 * Policeman - Chubby Oates
 * Soldier - Pat Gorman
 * Man with boat - Terry Walsh
 * Hopkins - Michael Pinder
 * Tramp - Stuart Fell
 * Spider Voices - Ysanne Churchman, Kismet Delgado, Maureen Morris
 * Arak - Gareth Hunt
 * Sabor - Geoffrey Morris
 * Neska - Jenny Laird
 * Rega - Joanna Monro
 * Tuar - Ralph Arliss
 * Guard Captains - Walter Randall, Max Faulkner
 * K'anpo - George Cormack

Uncredited cast

 * Doctor Who - Tom Baker
 * Guards - Steven Ismay, Leslie Bates, Harry Fielder, Dennis Plenty, Roy Pearce, Derek Hunt, Geoffrey Witherick, John Cash
 * Stunt Guards - Alan Chuntz, Stuart Fell, Billie Horrigan (all DWM 314)

Crew

 * Costumes - L. Rowland Warne
 * Designer - Rochelle Selwyn
 * Film Cameraman - Fred Hamilton
 * Film Sound - John Gatland
 * Film Editor - Bob Rymer
 * Film Sound - John Gatland
 * Incidental Music - Dudley Simpson
 * Make-Up - Deanne Turner
 * Production Unit Manager - George Gallaccio
 * Script Editor - Terrance Dicks
 * Special Sounds - Dick Mills
 * Studio Lighting - Ralph Walton
 * Studio Sound - John Holmes
 * Theme Arrangement - Delia Derbyshire
 * Title Music - Ron Grainer
 * Visual Effects - Bernard Wilkie

Uncredited crew

 * Producer - Barry Letts (DCOM: Planet of the Spiders)
 * Writer - Barry Letts (DCOM: Planet of the Spiders)
 * Grip - Jim Gomm (INFO: Planet of the Spiders)
 * Film Camera Assistant - Ian Punter (INFO: Planet of the Spiders)
 * Visual Effects Assistants - Ian Scoones, Richard Conway, Steve Bowman, Mat Irvine (INFO: Planet of the Spiders)
 * Make-Up Assistant - Sheelagh Wells (INFO: Planet of the Spiders)
 * Vision Mixer - Nick Lake (INFO: Planet of the Spiders)
 * Film Sound Assistant - Frank Brown (INFO: Planet of the Spiders)
 * Film Operatives Manager - Hugh Wilson (INFO: Planet of the Spiders)
 * Film Props - Albert Crush (INFO: Planet of the Spiders)
 * Assistant Floor Manager - Graeme Harper (INFO: Planet of the Spiders)
 * Grams Operator - Andrew Hunter (INFO: Planet of the Spiders)
 * Director's Assistant - Heather Dunthorne (INFO: Planet of the Spiders)
 * Inlay Operator - Dave Chapman (INFO: Planet of the Spiders)
 * Production Assistant - Marion McDougall (INFO: Planet of the Spiders)
 * Floor Assistant - Geoffrey Posner (INFO: Planet of the Spiders)
 * Technical Manager - Tommy Dawson (INFO: Planet of the Spiders)

Foods and beverages

 * The Doctor likens Sergeant Benton's coffee-making skills to those of Mrs Samuel Pepys.
 * Lupton offers Sarah tea.
 * The Two-Legs give the Doctor a mutton broth.

Individuals

 * The Doctor mentions being taught in the ways of escapology by Harry Houdini.
 * The Brigadier phones Sullivan, the UNIT Medical Officer.

Media

 * Sarah has worked for Metropolitan magazine.

Psychic powers

 * The Doctor is studying ESP.
 * Herbert Clegg shows the power of psycholotry.
 * The Lupton group's incantation "om mani padme hum" summons the Eight Legs to Earth.

References to real-world culture

 * Tommy reads "The Tyger" aloud, a poem by William Blake.
 * A comedian who performs prior to Clegg references the Archimedes principle.
 * The Doctor is familiar with Tibetan language and customs.

Technology

 * The Doctor uses electroencephalography on Herbert Clegg.
 * The Doctor uses an Image Reproduction Integrating System (IRIS).

The Doctor

 * The Third Doctor regenerates into the Fourth Doctor.

Story notes

 * This is the first time the term "regeneration" is mentioned on screen.
 * This is the first time we see someone other than the Doctor regenerate (K'anpo Rimpoche).
 * Though not credited, Barry Letts wrote this story with Robert Sloman. Therefore, this marks the only story in Doctor Who to be written and directed by the same person.
 * This story carries no on-screen producer credit for Barry Letts, as the BBC would only allow him to be credited as either producer or director.
 * Unusually, the reprise at the beginning of part six features multiple scenes that were not shown in part five before it reaches the cliffhanger point. Barry Letts explains on the DVD commentary that the reason for this is because the scenes were originally shot for part five, but he felt the "special effects backgrounds didn't really work" so he chose to cut them. However, this meant part six was running short, therefore Letts had to re-insert the cut sequences into the episode's reprise in order to fit the required timeslot.
 * This story features a large chase scene including Bessie, the Whomobile, a police car, a gyrocopter, a hovercraft and a boat.
 * Tom Baker is uncredited in the conclusion of Planet of the Spiders when Jon Pertwee transforms into Tom Baker. Since no regeneration was shown at the end of The War Games, this marked the first time since William Hartnell changed into Patrick Troughton in 1966's The Tenth Planet that an on-screen hand-over of the role had occurred. Significantly, therefore, it was the first end-of-season regeneration to show the incoming actor.
 * This is the only story Barry Letts directed (while also serving as producer) that was not written by Robert Holmes.
 * Though Harry Sullivan does not make his on-screen debut until the next story, he is mentioned in this one. When the Doctor is in a trance staring at the crystal, the Brigadier phones the medical officer and addresses the person on the other end of the phone as "Sullivan".
 * Terrance Dicks remarked in the DVD commentary that he wanted to make sure the Brigadier was present to witness the Doctor's regeneration so as to ensure there would not be a repeat of the events that occurred in Spearhead from Space where it took a considerable amount of effort for the Brigadier to be convinced that the Doctor had indeed changed his appearance.
 * Elisabeth Sladen is credited as "Sarah Jane" in Radio Times for parts two and three.
 * Nicholas Courtney is credited as "Brigadier" in Radio Times for parts one and two.
 * Cyril Shaps (Professor Clegg) is credited as "Professor Herbert Clegg" in Radio Times for part one.
 * Ysanne Churchman (Spider Voice) is credited as "Lupton's Spider" in Radio Times for parts four to six.
 * Kismet Delgado (Spider Voice) is credited as "Queen Spider" in Radio Times for parts four to six. She is credited on-screen together with Ysanne Churchman for part two, but not in Radio Times (the programme listing bills only Churchman).
 * Radio Times credits Maureen Morris (Spider Voice) as "Other Spider Voices" for part four, and as "The Great One" for parts five and six.
 * Walter Randall (Guard Captain) is credited as "First Guard Captain" in Radio Times for parts four and five.
 * Max Faulkner (Guard Captain) is credited as "Second Guard Captain" in Radio Times for parts four and five. He is not credited on-screen for part four because these sequences were intended for part five only.
 * George Cormack (K'anpo) is credited in Radio Times for part five, but not on-screen because these sequences were intended for part six only.
 * Although Kevin Lindsay (Cho Je) is credited on-screen and in Radio Times for part two, he does not actually appear in the episode, as his scenes were edited out prior to transmission.
 * The Brigadier's line "Well... Here we go again" was an unscripted ad-lib by Nicholas Courtney.
 * Parts of this story were recorded at the same time as parts of Robot. This not only meant that Jon Pertwee and Tom Baker were literally playing the Doctor at the same time, but also that Elisabeth Sladen, and to a lesser extent, Nicholas Courtney and John Levene, were having to rush back and forth between the two productions.
 * Jo Grant sends the Doctor a package containing the blue Metebelis crystal which the spiders covet, making this serial a sequel of sorts to The Green Death. This is also one of the first times that a past companion has played a role in a later story, although Jo does not actually appear in the story (she does, however, appear in the novelisation).
 * Barry Letts remarked in the DVD commentary that, in the scene where Clegg holds the sonic screwdriver and the images appear on the IRIS machine, he had originally considered using footage from The Green Death but he ultimately decided to use the Drashigs from Carnival of Monsters as he believed they would be more scary.
 * In A History of the Universe and aHistory, the scenes set on Metebelis III are arbitrarily dated to 5433 (the crash was 433 years ago and the ship is capable of intergalactic travel).
 * Incidental music from part two exists.
 * The phrase "Where there's life, there's hope", is a quote taken from the Roman philosopher Cicero and Terence's work Heauton Timorumenos.
 * Tommy's story is similar to that of the protagonist of the novel, a story of a mentally challenged man whose intellect is artificially boosted to genius levels. However, the protagonist of that story, Charlie Gordon, later suffers a regression of intelligence, while Tommy's intelligence boost is permanent and without any apparent drawbacks.
 * John Kane (who played Tommy) was very new to television at the time of this story and had mainly worked in theatre where he often ad-libbed. When he was taking a taxi to BBC Television Centre for his first day of filming he asked the driver if he could take him to "where they make those television programmes" (speaking like Tommy due to his impulse to ad-lib). He proceeded to tell the driver that he was "going to see [his] friend Doctor Who". The driver continued to ask Kane questions about his time with his 'friend', making Kane more and more anxious. When they arrived at Television Centre, the driver went out to speak to the security guard briefly who then called Kane over and told him that Doctor Who had left in his TARDIS and wasn't there, but would wave to him next time he was on TV. The driver offered to take Kane back, but he insisted on staying and then proceeded to tell the guard the truth after the driver had left.
 * This is one of two regeneration stories without any scenes inside the TARDIS, the other being TV: The Night of the Doctor.
 * This is the first of two Doctor Who stories to feature giant spiders. The other being Arachnids in the UK, released 44 years later.

Ratings

 * Part one - 10.1 million viewers
 * Part two - 8.9 million viewers
 * Part three - 8.8 million viewers
 * Part four - 8.2 million viewers
 * Part five - 9.2 million viewers
 * Part six - 8.9 million viewers

Myths

 * Roger Delgado's Master was originally to have been written out in Planet of the Spiders, and after the actor's death the story was revised to incorporate Lupton in place of the Master.
 * It is true that had Delgado not died, he would have been written out in the final story of season eleven. During the filming of Frontier in Space, he had informed Barry Letts that he would only appear as the Master in one more story. Letts agreed to the request, seeing it as an opportunity to dramatically end Season 11. He asked writer Robert Sloman to help him write a story which would at last define the relationship of the Doctor and the Master, before having the Master sacrifice himself to save the Doctor. Sloman delivered at least an initial round of scripts, called The Final Game, before Delgado's death forced the complete suspension of the story line. Planet of the Spiders was a wholly different story, save perhaps for Barry Letts' desire to incorporate certain Buddhist philosophies.


 * A frequent corollary to the above is that The Final Game would have also incorporated the regeneration of the Third Doctor.
 * Sloman had delivered scripts to Letts two weeks prior to Delgado's death on 18 June 1973. Pertwee didn't announce his retirement until after his request for a raise was denied in December 1973. The first scripts of The Final Game presumably had not included any elements pertaining to the Doctor's regeneration, because writer Robert Sloman didn't know Pertwee was going to leave.

Filming locations

 * Tidmarsh Manor, Tidmarsh, Berkshire
 * Bloomfieldhatch Lane, Stratfield Mortimer, Berkshire
 * Membury Airfield, Membury, Wiltshire
 * River Severn, Westbury-on-Severn, Gloucestershire
 * Mortimer station, Stratfield Mortimer, Berkshire
 * Mereoak Lane, Stratfield Mortimer, Berkshire
 * Le Marchant Barracks, London Road, Devizes, Wiltshire
 * BBC Television Centre (TC1, TC6, TC8), Shepherd's Bush, London

Production errors

 * The Doctor's flying car is a different colour in the studio (gold rather than silver). This is due to the silver Whomobile reflecting the yellow backdrop used for the CSO screen.
 * In part two, when Lupton blasts Benton, the blast noticeably comes from beneath his outstretched hand rather than from his fingers.
 * In part two, the guard attacked by the spider clearly prepares himself for a fall by sticking his hands out in front of him.
 * In part two, Richard Franklin trips up on the word "much" when he tries to say, "No, it's much better you go by yourself."
 * In part two, as the police car pulls a three-point turn whilst giving chase, the Whomobile can be seen sitting stationary in the distance.
 * When Tommy meets Sarah in part one, he refers to himself as "Tom". Yet when she sees him again in part three, she calls him "Tommy".
 * In part four, when the Queen spider is talking to Lupton and his spider, the base of the Queen's throne can be seen flexing up and down as the spider moves.
 * In part four, when Tommy collapses after looking into the crystal, it is clearly on a table. When he comes to, he is holding it.
 * In part six, the puppet strings for the Great One's legs can be partially seen, as can some of the smaller Eight Legs' strings once they have overturned in pain from the infinite psychic feedback of the crystal web.

Continuity

 * Jo Grant sends the Doctor a package containing the blue Metebelis crystal. (TV: The Green Death)
 * Mike Yates refers to when he met Sarah. (TV: Invasion of the Dinosaurs)
 * The Doctor previously mentioned the hermit who lived behind his house. (TV: The Time Monster)
 * When the Doctor explains the workings of the TARDIS to Mike, he says, "You speak as if she were alive," and the Doctor replies, "Yes. Yes, I do, don't I?" (TV: An Unearthly Child, The Doctor's Wife, et al.) This was the same thing Jo Grant said when the Doctor talked about the TARDIS having moods, to which she responded, "You talk as if she was alive." (TV: The Time Monster)
 * PROSE: Interference - Book Two presents an alternative regeneration sequence when the Eighth Doctor is manipulated into changing his past by Faction Paradox, resulting in the Third Doctor regenerating on the planet Dust when he is shot; the timeline returns to normal following the events of PROSE: The Ancestor Cell.
 * The Eight Legs returned in PROSE: The Eight Doctors, PROSE: Return of the Spiders, AUDIO: The Eight Truths and AUDIO: Worldwide Web.
 * The Fifth Doctor in the PROSE: Light at the End of the Tunnel tries to fight off his phobia of spiders when he goes inside a large pipe.
 * The Eighth Doctor still has a phobia of spiders in PROSE: The Scarlet Empress.
 * Professor Clegg divines that the Brigadier's wristwatch was given to him eleven years earlier in a hotel room by a woman named Doris, prompting a somewhat embarrassed reaction from the Brigadier. After his retirement, the Brigadier marries a woman named Doris. (TV: Battlefield)
 * K'anpo Rinpoche regenerates from a Caucasian appearance to an Asian appearance. Melody Pond similarly changed her ethnic appearance in one of her regenerations. (TV: Let's Kill Hitler)
 * In PROSE: Love and War, it is revealed that the Doctor spent ten years alone wandering in the vortex dying of radiation poisoning before returning to UNIT. PROSE: Ancient Whispers and The Loneliness of the Long-Distance Time Traveller are set during this time.
 * A Time Lord's change of appearance is referred to as a "regeneration". (TV: The Deadly Assassin, Castrovalva, The Five Doctors, et al.)
 * When needing to boost a human's psychic powers, the Eleventh Doctor later returns to Metebelis III to retrieve another crystal. (TV: Hide)
 * When Sarah Jane and the Brigadier discuss the Doctor's three-week absence, the Brigadier recounts how "one time, I didn't see him for months; what's more, when he did turn up, he had a new face." (TV: The Invasion, Spearhead from Space)
 * This is the second time the Doctor has possessed a crystal that can emit powerful radiation and mutate certain beings after prolonged exposure to enough radiation. (TV: The Mutants)

DVD release
This story was released as Doctor Who: Planet of the Spiders.

Released: Special Features:
 * Region 2: 18 April 2011
 * Region 1: 10 May 2011
 * Region 4: 2 June 2011
 * Commentary by Elisabeth Sladen, Nicholas Courtney, Richard Franklin, Barry Letts, and Terrance Dicks.
 * The Final Curtain documentary
 * John Kane Remembers featurette
 * Directing Who With Barry Letts documentary
 * Now and Then featurette
 * Planet of the Spiders 102 minute omnibus
 * Omnibus trailer
 * Photo Gallery - Includes unreleased incidental music from Part Two.
 * PDF: Radio Times Listings

Digital releases
This story is available:
 * in iTunes stores (Australia, Canada, France, Germany, UK and US) as part of the Doctor Who: The Classic Series collection Doctor Who: The Best of The Third Doctor, which additionally includes the stories Spearhead from Space, The Three Doctors and The Green Death;
 * in non-European iTunes stores (Australia, Canada and US) as a standalone season of Doctor Who: The Classic Series;
 * on Amazon Video (UK) as Season 74 of Doctor Who (Classic) series;
 * for streaming through BritBox (US) as part of Season 11 of Classic Doctor Who.

Video release
This story was released on VHS as per follows:


 * Region 2: April 1991
 * Region 4: September 1991
 * Region 1: May 1994