The Caves of Androzani ( TV story ) The Caves of Androzani was Peter Davison ' s final regular appearance as the Doctor . It was also Graeme Harper ' s first credited " Doctor Who " director ial gig . Widely praised by fans , " Caves " was voted the single best televised " Doctor Who " story in a 2009 poll conducted by " Doctor Who Magazine " . ( DWM 413 ) As a regeneration story , it offered many unusual elements . Perhaps the most obvious was that it was written by Robert Holmes . Although the most prolific writer of the 1963 version of the programme , this was his only regeneration story . " Caves " was also the first regeneration story to allow for a brief scene with the incoming Doctor . Unlike any of his predecessors , the new Doctor was given the final words of the story — something that would happen in regeneration stories of the revived series . It was also the first time the Doctor willingly and explicitly underwent a regeneration solely to save a companion , which the Doctor would only do again in his ninth incarnation , ( TV : " The Parting of the Ways " ) and his tenth incarnation . ( TV : " The End of Time " ) Furthermore , it was the first time since 1966 ' s " The Tenth Planet " that the Doctor regenerated before the end of the then - current series , and the first since " The Tenth Planet " that occurred inside of the TARDIS . From a behind - the - scenes perspective , Harper ' s direction was hailed by those involved with the production as highly innovative . Particularly noteworthy were Harper ' s more free use of camera movement than usual at the time and his direction from the studio floor . Harper ' s energetic and more personal directorial style sharply contrasted most who preceded him . Unlike Harper , most directors of the 1963 version of " Doctor Who " generally preferred to work in the booth and relay their messages to the actors and crew through the production assistant stationed on the floor . Peter Davison , in particular , found Harper ' s more direct style much to his liking . He lamented he had waited until his last story to receive this bolder style of direction , and that he would ' ve stayed on the series longer if this directorial style was present during more of his tenure ( DCOM : " The Caves of Androzani " ) . Another unique aspect of the production was its use of Shakespearian . Morgus , the principal villain of the piece , sometimes turned away from the characters and spoke his thoughts aloud , often appearing to break the fourth wall in the process by gazing into the camera . Though apparently the result of a mistaken impression about the script by actor John Normington , Harper kept the asides in , feeling they effectively ramped up the dramatic tension . ( DCOM : " The Caves of Androzani " ) Synopsis . Arriving on the barren world of Androzani Minor , the Doctor and Peri find themselves embroiled in a long running , literal underground war . At the heart of the conflict is a substance called Spectrox - both valuable and deadly ! The Doctor & Peri wind up being poisoned by the material , which is killing them slowly and painfully unless they can find a cure . As the conflict heats up and the situation gets more desperate , the Doctor realises time is running out - both for Peri and himself . . . Plot . Part one . The TARDIS lands on Androzani Minor , one of twin planets in the Sirius star system . The Doctor and Peri decide to explore a set of tracks that lead into some nearby cave s . The Doctor finds a spaceship has arrived , carrying a strange cargo . Deep in the caves , a soldier is killed by a monster . In another part of the caves , Peri catches her foot in an unknown , sticky and stringy substance . As the Doctor pulls her leg free , he gets some of the substance on his hand . Despite noticing that the substance has a strange stinging sensation to it ( something Peri also complains about ) , he is unconcerned . As they keep exploring deeper into the cave system , Peri asks why the Doctor wears a stick of celery , he explains that it is a safety precaution . He is allergic to certain gases in the praxis range of the spectrum ; in their presence , celery turns purple . They discover a hoard of weapons and hear several footsteps . Soldiers capture them and take them to their leader , General Chellak . As the two explain their innocence to Chellak and Major Salateen , there is a call from Trau Morgus , a business conglomerate leader on Androzani Major and CEO of the Sirius Conglomerate . Believing the two to be working for gunrunners Stotz and Krelper , he loses all interest in them and orders their deaths after seeing that Chellak ' s " gunrunners " are not his own men over holographic communication . Deep in the caves , the masked madman Sharaz Jek has monitored the broadcast between Morgus and Chellak . He is delighted at Peri ' s beauty . Meanwhile , Chellak tries to reason with Morgus in an attempt to get him to relent on his decision to execute the prisoners , telling him that Peri and the Doctor have been fully cooperative and might give them more information if they are kept alive . But Morgus refuses , telling Chellek that there can be no negotiations with traitors . In their cell the Doctor and Peri await their deaths . The Doctor ponders what they have stepped into , noticing how Morgus lost all interest in them once he had had his look at them and his talk of fighting against android rebels . Peri comments that it hardly matters ; the authorities seem bent on making the two of them fall guys for whatever is going on . The Doctor apologises to Peri for getting them into this mess , telling her that curiosity has always seemed to be his downfall . Their conversation then turns to the strange fungus Peri stepped in ; Peri complains that the rash on her leg is starting to develop into blisters , and the Doctor tells her that the same is happening to his hand , noticing that the substance must have some highly toxic properties . Peri grimly points out that whatever it was , it probably will not manage to kill them before the executioners can . Meanwhile , in his lair , Sharaz Jek keeps the military base under close surveillance through hidden cameras . Looking at the Doctor and Peri in their cell and the soldiers preparing for the execution outside , he starts issuing orders to his androids . In the cell , the Doctor ' s thoughts turns to the " spectrox " , which both Chellak and Morgus were discussing during their interrogation of them . He wonders what it is and why Morgus named it the " most valuable substance in the universe " . Peri asks him if he really does not know , and the Doctor answers that even his knowledge is not limitless . As they talk , a secret door in the back of the cell opens and a figure steps inside . . . A business conversation between Morgus and the President of Androzani Major reveals the full picture of the Spectrox crisis . Spectrox is a powerful drug produced by bats in Androzani Minor ' s caves , which is the only known source of the drug . Spectrox is highly valued by the people of nearby Androzani Major for its ability to extend life and keep ones youthful looks somewhat intact . The spectrox mines are controlled by Morgus , but the operation is threatened by the masked Sharaz Jek and his army of android s , causing public tension on Androzani Major over limited supplies . Morgus has funded a military operation by Androzani Major ' s government against Jek ' s androids . He has also secretly backed a gunrunning group to deliver weapons to Jek to profit from the war . As Morgus and the President watch on a monitor , the Doctor and Peri are brought to the execution squad , dressed in red to hide the blood of their impending wounds . General Chellak asks if they have any last words ; the Doctor tells him the whole thing is a mockery of justice , while Peri tells him just to get it over with . The soldiers step forward and take aim . On command , they pump bullets into the Doctor and Peri . Part two . Chellak has the soldiers check their weapons . As the bodies are cut free of the execution posts , Morgus switches off the monitor . He tells the President anyone without a valid work permit has been sent to Eastern labour camps to reduce crime . The President realises Morgus has been closing plants in the West and opening them again in the East . If he accepts Morgus ' suggestion , the same people will be working for him without pay . It turns out that the Doctor and Peri have been rescued by Sharaz Jek , who was watching them and had prepared android duplicates to take their place in the execution . They are taken to his base to become his companions in exile . Chellak and Salateen go to look at the bodies . When they turn out to be androids , Chellak realises his career is at risk . He decides to not let anyone know about it . Meanwhile , the Doctor asks Jek if he could show him and Peri the way to the surface , but Jek explains that he intends to make them stay with him and keep him company . He assures them , with a hint of threat in his voice , that he will take care of their every need . Meanwhile , Stotz is having trouble . Krelper is getting fed up with the lack of pay and their recent string of failures and wants to leave the gunrunning enterprise . But when Stotz threatens with killing him , Krelper relents and Stotz decides to let him live for the time being . At Jek ' s base , the Doctor and Peri complain of rashes and cramps where they touched the sticky substance in the caves . Jek returns , and Peri asks him why he wants to keep them prisoners here . Jek answers that he is attracted to her beauty and that he likes the idea of having the Doctor as an intellectual sparring partner . He then tells the Doctor that he sees him as the most expendable person in this arrangement and he therefore expects him to be obedient towards him , warning him if he does not submit , then he will kill him , but Peri , on the other hand , he intends to keep alive forever . When Peri answers that eternal life is impossible , Jek explains that refined spectrox can extend someone ' s life , forever if need be , and he now owns all of it . " Until the army takes it away from you , " comments the Doctor dryly , but Jek angrily retorts it will not happen . Thanks to his monitoring equipment , he knows the army ' s every move , and so far their fight against his androids have been slow and very costly in manpower for them ; at the current rate it will take five years for the army to actually threaten his operations and by that time he expects the people of Androzani Major to have already risen up and forced the Presidium to agree to his terms : they can have all the spectrox they want once the head of Morgus lies at his feet . Meanwhile at Morgus ' headquarters , Morgus is surprised to hear from Timmin that the copper mine has exploded . This takes care of overproduction and makes the price of copper rise . Morgus wants every employee to leave their place and stand in silence for a minute but then changes his mind and says half a minute . Back at Jek ' s base , the Doctor meets Salateen . He has been a prisoner here , too . Jek captured him months ago and replaced him with an android that looks like him . The real Salateen resignedly realises Jek will probably kill him now he has them for company . When the Doctor tries asking him about the weird symptoms he and Peri are experiencing and explains how they got them , Salateen breaks into a bitter laugh . He tells that they are in the first stages of spectrox toxaemia , a very serious form of poisoning contracted from exposure to unrefined spectrox . Their symptoms are only going to get worse from here and the condition will eventually kill them in a few hours . While there is an anti - toxin , it requires the milk of the queen bat . Due to the mining activity , all the bats have fled to deeper levels of the caves , where there is no oxygen , making it next to impossible to acquire . Stotz contacts Jek and tells him his ship is in good shape and it wasn ' t his fault that the androids didn ' t show up . Before Jek leaves to meet with Stotz and the gunrunners , Peri asks why he wears a mask . Jek flies into a rage . Shaking with anger , he explains that he was once Morgus ' business partner in the spectrox business . One day when he was working on Androzani Minor , a mud burst erupted , but Morgus had betrayed him by giving him faulty detection instruments , so he had no warning of the burst . Though Morgus left him to die , Jek managed to survive , but was horribly scalded and disfigured . He has ever since tried to exact revenge on Morgus . Done with his explanation , he leaves them under the watch of his androids as he ventures out to meet up with Stotz . In the lower levels of the caves , Jek meets up with Stotz and the gun - runners and announces that he will only hand over half of the promised spectrox , as they have failed to deliver the shipment . This greatly angers Stotz who demands all of the payment he was promised , but Jek refuses , telling him that it is their own fault they lost the weapon shipment . Fuming , Stotz threatens to stop doing business with Jek for good , but Jek says he fully well knows the value of spectrox and can very easily find himself another weapon supplier . In Jek ' s HQ , the Doctor manages to get close to and reprogram the android guarding the entrance to the lair . Him , Peri , and Salateen then uses this opportunity to make their escape . Meanwhile , Stotz pretends to relent to Jek ' s offer , but as Jek leaves to get the spectrox , he points out to his fellow gun runners that they can just follow Jek back to his base , walk past his androids , kill him and steal his spectrox . The Doctor , Peri and Salateen head into the lower levels of the caves to find the queen bat . Unfortunately , they encounter one of Jek ' s android guards who opens fire at them . One shot grazes the Doctor on the temple which knocks him unconscious . Salateen , using Peri as a human shield , fires back at the android and destroys it , he then forcibly drags her away from the Doctor despite her protests . The Doctor regains consciousness and discovers Peri has vanished . He goes to find her . Jek returns to his base , but flies into a rage when he discovers that Peri has gone . The Doctor takes cover behind a rock as Stotz and the gun runners enter . One of the gun runners is attacked and killed by a fierce magma beast . The other gun runners open fire on the beast and it kills another gun runner . It ignores the bullets and approaches the rock where the Doctor is crouching . Part three . The beast is distracted by the gun runners . It turns on them again . The Doctor escapes as the gun runners retreat . Meanwhile , Peri is taken with Salateen to General Chellak . She tells him what has happened . Stotz and the gun runners meet Jek . The Doctor meets Jek again . He tortures the Doctor and the Doctor finally tells him that Peri has been taken to Chellak . Stotz arrives . Jek tells him to take the Doctor to Androzani Major to see if he is a government spy . The Doctor is in the third stage of spectrox toxaemia and is feeling unwell , but Stotz doesn ' t care ; the Doctor will live long enough to be questioned . In the army base , Peri also isn ' t feeling well , but General Chellak doesn ' t care ; she and the Doctor have been working with Jek . Chellak orders an assault on Jek ' s base . Salateen agrees to tell Morgus about the assault and to throw Jek off guard when he broadcasts a message . Jek discovers the real Salateen is free to walk around the planet , leaving Peri unguarded . Meanwhile , Stotz chains the Doctor in the bridge of his spaceship and calls Morgus . As Stotz discusses the situation with Morgus , the businessman sees the Doctor still alive . He tells Stotz that Chellak faked the attack on Jek ' s base . Morgus is worried the President will see his double dealings . He tells Stotz to remain in orbit and Stotz , furious , leaves the Doctor on his own . When Stotz is gone , the Doctor tries to escape . He pulls himself free of the wall and uses the power core in the centre of the ship ' s bridge to sear the chains from his hands . He is still very weary from the Spectrox but programs the spaceship to land or " crash " on Androzani Minor . Meanwhile , Morgus , fearing deception , invites the President into his office and opens his private lift so the President can leave . The President doesn ' t realise it ' s just an empty shaft . Morgus pushes the President into the lift and he falls to his death . Morgus orders Timmin to have the lift maintenance engineer shot and makes his own plans to travel to Androzani Minor to put the situation right himself . Meanwhile , Jek has kidnapped Peri and taken her back to his HQ , where he finds the Doctor has gone . He is now insane and needs Peri ' s beauty to forget the trouble that Morgus has put him in . Peri tells him the army will attack soon , but Jek already knows that - he has changed the recognition code for the belt buckle . General Chellak and his men are in for a shock . . . The Doctor is in the centre of the ship ' s bridge . Suddenly an extreme tiredness overtakes him , and his vision becomes distorted . However , he manages to shake it off and return to clarity as he hears shouting at the door . It is Stotz , who has been alerted by the loud , rumbling noise from the landing procedure . He demands the Doctor unlocks the door , but the Doctor refuses . Stotz shouts for something to cut the door open with , and tries to coax the Doctor into opening the door willingly , but the Doctor rebuffs him , telling him he rather should focus on finding something to hold on to , as their landing could easily be a rough one . Stotz ' s men proceed to cut a hole in the door open with a blowtorch , but the edges of the cutout is too hot for Stotz to reach the door controls , so instead he points his weapon at the Doctor and threatens to shoot him . The Doctor notices that it is hardly a persuasive argument , since he will die soon anyway unless he can cure his toxaemia . Stotz gives him to the count of three to surrender , but the Doctor is unmoved by this , and he tells Stotz that he owes it to Peri to find the antidote as he got her into danger in the first place . " So you see , " shouts the Doctor defiantly as Stotz finishes his countdown , " I ' m not gonna let you stop me now ! " . Part four . The ship ' s rocket pods fire at the last moment , throwing Stotz ' s aim off and allowing the Doctor to violently land the ship on the surface of Androzani Minor . Still experiencing the effects of the Spectrox poisoning , the Doctor escapes from the spaceship . Krelper and another gun runner chase after him . Meanwhile , General Chellak plans the real assault on Jek ' s base , making him believe an attack lies elsewhere . As the assault force , guided by Salateen , heads towards the base , they come to a hold as they run into an android . Salateen assures them that there is nothing to fear , as the belt buckles will protect them , but as he moves towards the android to prove this , he is immediately gunned down . Panic erupts in the ranks as the soldiers realise that the signal is not working , and they frantically return fire . They eventually manage to disable all of Jek ' s androids , but at a very high cost of lives . Meanwhile , Krelper and his cohort are still chasing the Doctor . He approaches a cliff and falls from it . Rendered helpless for a moment , he is unable to get up as Krepler and the other gunrunner approaches him , but just they are about to kill him , a mudburst begins and they decide to leave the Doctor be and retreat to the safety of the ship . The Doctor gets to his feet and makes his way into the caves to save Peri . Chellak and the few remaining soldiers have no choice but to push against the mudburst . Chellak sees Jek and chases him to his base . Once there , he struggles with Jek until he pulls his mask off . He is so horrified at Jek ' s scalded face that Jek is able to push him outside into the path of the mudburst . Jek goes to Peri . She screams at the sight of Jek ' s face and Jek himself lets out a cry of agony . The Doctor arrives , struggling to hold off the effects of the Spectrox poisoning , and the regeneration that would rid him of the infection . When the Doctor explains that he can hold his breath much longer than a human and therefore has a better chance to survive in the lower parts of the caves , Jek provides him with an oxygen tank and directions , so he can find and milk the queen bat . As the Doctor departs to get the milk , Morgus arrives on the planet . He finds Timmin has betrayed him and taken his dirty dealings to the government , which means he is now deposed from power and isolated from his wealth . Morgus declares that he is not beaten yet , and quickly works out a deal with Stotz . Krelper and his friend , however , have decided to cut their losses and want no part in it . Stotz pretends to accept this only to shoot and kill them as soon as their guard is down . Morgus and Stotz continue on ahead , plotting to secure Jek ' s private stash of spectrox so they may disappear quietly to another planet . The two make their way to Jek ' s base , lured by extractor fans that Jek is using to keep the base temperature cool for Peri . Morgus orders Jek to give him the Spectrox . Jek sees Morgus and , consumed by rage , forgets all about Peri and everything else . He pulls off his mask , showing Morgus his scalded face . As Morgus looks at Jek in shock , Jek throttles him . Stotz opens fire on Jek , but the Salateen android returns and kills him . With his last ounce of life , Jek pushes Morgus ' head into his extractor fans . Morgus dies in seconds and the extractor fans short circuit and burst into flames . Jek dies in the arms of the Salateen android , giving it his last orders to hold him . The Doctor arrives just after the battle , and escapes , but the Salateen android stays where it is as the fire destroys Jek ' s base . The Doctor takes the unconscious Peri back to the surface and the TARDIS , but a mud burst is on its way . While he unlocks the TARDIS , the Doctor spills half the bat ' s milk in the sand . He manages to open the door , get inside the TARDIS and dematerialise as the planet ' s surface explodes in boiling mud . Inside the TARDIS , the Doctor feeds Peri all of the remaining bat ' s milk , then collapses on the floor of the TARDIS , now so close to death that he is starting to doubt that regeneration is possible , saying aloud " Is this death ? " . Peri recovers to find the Doctor lying in pain on the floor . The Doctor quickly explains he cured her with the bat ' s milk , but he only had enough for her . He tells Peri that there ' s nothing she can do , that he will be going soon , and it ' s time to say goodbye . Peri encourages him not to give up and pleads that he can ' t leave her now . He then says that he " might regenerate " , but he doesn ' t know for certain that he will be able to , because the process " feels different this time " . A bright glow surrounds the Doctor as his image distorts ; he begins hallucinating his previous companions urging him to live , telling him the universe still needs him . He is particularly affected by the vision of someone who died , and his final word is , " Adric ? " A vision of appears , laughing at the Doctor and telling him to die . The visions of his companions begin to swirl , all their voices overlapping together and drowning out the taunts of his foe . The glow grows brighter and covers the Doctor . As the visions subside all at once , it fades to reveal the Doctor ' s new incarnation , a man with a sharp gaze and curly blond hair atop his head . Peri moves toward the regenerated Doctor and addresses him by name . The Doctor , now sitting up and fully alert , challenges his now - detoxified assistant with the words , " You were expecting someone else ? " Speechless , she trips up , " I , I , I . . . " . He ironically scolds her , " That ' s three I ' s in one breath . Makes you sound a rather egotistical young lady . " Peri asks , " What ' s happened ? " He grandly declares , " Change , my dear , and it seems not a moment too soon , " staring forward with a proud grin and a glint in his eye . DVD , VHS and audio releases . DVD releases . Released as " Doctor Who : The Caves of Androzani " , this release was the third of 2001 . Released : Contents : Rear Credits : Notes : Special Edition release . This story was released as " Doctor Who : The Caves of Androzani : Special Edition " . Released : Special Features : Notes : VHS releases This story was released as " Doctor Who : The Caves of Androzani " . Released :