The Mind of Evil ( TV story ) The Mind of Evil was the second serial of the eighth season of " Doctor Who " . It brought a radical change in the way UNIT was portrayed . Instead of being a primarily investigative body interested in alien or unexplained phenomena , here UNIT was mostly seen as a simple security force , guaranteeing the safety of international diplomats . In other words , the " United Nations " portion of their acronym was stressed over the " Intelligence Taskforce " bit — as later happened in such stories as " Day of the Daleks " and " The Time Warrior " . This forced the plot to partially concern itself with international espionage , thus lending an almost Bondian veneer to proceedings . The internationalism of the plot even allowed for highly unusual scenes of the Doctor conversing in a real language other than English . Indeed , as of the seventh BBC Wales series , " Evil " was the only story which used English subtitles for the Doctor ' s speech . Meanwhile , the main plot about the mind - control device was something writer Don Houghton intentionally included as an homage to . Behind the scenes , " Evil " went badly over budget , thanks in no small part to one of " Doctor Who " s rare usages of a real helicopter in the concluding episode . An unimpressed Barry Letts therefore withdrew director Timothy Combe from his informal " director ' s rota " , and Combe never worked on the programme again . Following the destruction of its colour telerecording s , " Evil " became the " most missing " serial of the Jon Pertwee era , in that not even a frame of it survived in colour on any broadcast - quality medium . Fortunately , the whole of it remained available in monochrome , due to the fact that some of BBC Enterprises ' overseas customers required black - and - white transmission prints . Additionally , a few colour clips survived from an off - air home recording , which allowed for some scenes to be recoloured for the 1998 VHS release . Its DVD release marked its complete restoration , with all six episodes recoloured . Synopsis . UNIT is handling the security for the World Peace Conference in London , but the Master is plotting to plunge the world into war by wrecking it . Posing as Emile Keller , a Professor of Criminology , he goes to Stangmoor Prison in England with a machine that apparently removes the negative ( or evil ) impulses from the minds of hardened criminals . Actually , the Keller machine is a weapon : it contains an alien mind parasite that stores , and feeds on , these evil impulses . Unsuspected because of his forged credentials , he secretly supplies guns to the prisoners and uses the mind parasite to start a riot by stirring up hostility among them , in which they take control of the prison . He plans to use them to seize a nerve gas missile being transported by UNIT , with which he hopes to destroy the Peace Conference . In case his plan to hijack the missile is thwarted , he intends to use the mind parasite ( once it has fed sufficiently ) to wreck the Peace Conference by murdering the American and Chinese delegates , who are to be killed by the mind parasite ' s telepathic powers . Plot . Episode one . The Third Doctor and Jo Grant arrive at Stangmoor Prison to view a demonstration of the Keller Machine , developed by Swiss scientist Emil Keller , which is claimed to cure anti - social behaviour by extracting evil impulses from the mind . Professor Kettering , acting on behalf of the absent Keller , reports over a hundred successful tests on Europe an prisoners . The Doctor ' s open scepticism is apparently justified when the machine overloads , and the subject , a hardened criminal named Barnham , is rendered comatose . Meanwhile , UNIT is busy overseeing security at the first World Peace Conference . Things are not going too well , as the Brigadier attempts to calm Captain Chin Lee , furious at the apparent theft of classified documents from the Chinese delegation . Later , Chin - Lee reports even worse news : the Chinese delegate is dead . Meanwhile , Captain Yates is assigned to lead a small UNIT platoon in disposing of the Thunderbolt , an outlawed nerve gas missile . Arthur Linwood , a medical student witnessing the Keller demonstration , is found dead near the Keller Machine , his face frozen in terror , covered in bites and scratches . His medical history shows a morbid fear of rat s . Professor Kettering is examining the machine when it becomes active on its own . Kettering has a vision of waves of water and dies of an apparent heart attack . Investigating his death , the prison medic , Dr Summers , is mystified that his symptoms are consistent with death by drowning . The machine ' s activity also appears to coincide with an increase in hostility in the prison population . The Doctor is worried that the machine has power over people ' s minds and is growing more powerful . As suspected , Kettering ' s medical files show a morbid fear of water . Later , as the Doctor examines the machine , it activates again . He is seized by terror as the room appears to erupt in flames . . . Episode two . Jo enters the room and breaks the hold that the machine had over the Doctor . The Doctor is initially cross at Jo for disobeying his orders . Jo presents the report on Kettering ' s death and he tells Jo that he saw fire when the machine had a hold of him . He tells Jo that he once saw a planet burn and the machine used this story to attack him . Yates enters with orders to bring the Doctor back . The Doctor refuses and Yates tries to use force until the Doctor counters him with Venusian Karate . Yates tells the Doctor about the peace conference and the death of the Chinese Delegate which peaks the Doctor ' s interest . He leaves Jo in charge of the prison and orders her to get the Governor to lock and bar the doors . Chin Lee is using a public payphone whilst Benton is waiting at a safe distance , keeping an eye on her . Lee leaves the booth and uses her mind control to cause Benton to faint . Lee escapes . When Benton awakens he tries to pursue her but she is hidden . Benton reports to the Brigadier who disbelieves his story of fainting and is cross . The Doctor and Yates enter . An electrician outside the UNIT headquarters is working on the telephone line . He is revealed to be the Master who has bugged the line and hears the plans for the movement of the missile . He is then picked up by an official car . Before the Doctor agrees to help the Brigadier he makes him promise that he will contact the ministry and put a ban on the Keller Process . Once the Brigadier agrees to this they head off to meet the new Chinese Delegate , Fu Peng . Yates makes a phone call ( overheard by the Master ) organising a motorcade for the missile at seven o ' clock the next day . When the Brigadier and the Doctor enter the Chinese Delegate ' s hotel room , he is initially cold towards them until , to the Brigadier ' s disbelief , the Doctor speaks with him in Chinese . The two go off to drink tea together , leaving the Brigadier a bit miffed . A cleaner is shown into one of the cells in the prison . Barnham is fit as a fiddle and has a conversation with Jo whereby he admits that he remembers nothing from before he awoke in the hospital bed . Summers tells Jo that the process has removed all negative impulses from Barnham - rendering him somewhere between an idiot and a saint . The clamour of the prisoners draws the guard supervising the cleaner out of the cell momentarily . The cleaner hides a gun under the pillow . Shortly afterwards a prisoner , Mailer , is brought in . The guards distract themselves by playing chequers whilst Mailer checks for the gun . Whilst the Doctor and Peng chat , the Brigadier doesn ' t get to ask any of his questions . They are soon led out with the Brigadier frustrated . The food arrives and Mailer takes the guards hostage . The Doctor speculates that there must be a link between the Keller Process and the death of the delegate . Yates presents the Brigadier with the plans for the movement of the missile . The Brigadier makes a comment with regards to Benton losing track of the Chinese girl . The Doctor realises that this is the link between the two things . He suggests that the Brigadier puts out a general alert for Lee . Lee meets up with the Master . He says that he has another task for her . She is distressed by this but the Master hypnotises her . Her task is to kill the American delegate . He sends her away . The prisoners are mutinying led by Mailer . Mailer says they need more hostages and goes to the medical ward . Jo and Summers are in a state of panic when Mailer bursts in and takes them hostage . The Brigadier is told of the fact that Lee has returned back to the Chinese Delegate ' s room and rushes off . Lee rings the American Delegate and tells him that his Chinese counterpart wishes to see him . The American Delegate is unsure but eventually complies . Lee opens the door and hides . The American Delegate let ' s himself in . Lee closes the door behind him and asks him to sit down . She switches the light off and the whirring resounds in the delegate ' s ears . He sees the approach of a dragon and cowers in fear . Episode three . Chin Lee is interrupted by the Brigadier and the Doctor who see the dragon . The Brigadier fires his gun and the dragon disappears . Lee falls into a faint . The Doctor says it is a collective hallucination . The American Delegate is on the floor unconscious through acute shock . The Chinese Delegate finds an amplifier behind Lee ' s ear and believes it is linked to the Keller Machine . The riot at the prison continues . Mailer is told that the prison is surrounded but he is still confident as the prisoners have hostages . The Doctor considers Lee to be a conduit to a larger threat . Lee awakes and the Doctor begins to interrogate her in Cantonese . Mailer is told that the phone lines are down . They go into the cell where Jo and Summers are . Summers tries to attack the guard but is thwarted . He is told he is to send a message to the Governor demanding a safe exit from the prison . Jo is left alone in the cell . There is an issue with the crane needed to move the missile which is delaying the process . The Doctor brings Lee to the Brigadier . Yates rings and tells the Brigadier of the hold up with the missile . Yates asks after Lee . The Brigadier tells him everything . The Master overhears this and orders his driver to take him to the prison . Lee tells the Brigadier of her association with Keller . Lee says she has been in the processing room but can ' t picture it . The Doctor says she is suffering from post - hypnotic block and realises that the Master is behind all this . Emil Keller is the Master . Jo is being moved at gunpoint . The Governor is refusing to negotiate . Summers is furious . The Governor intends on waiting it out . Summers asks what he plans on doing with Jo . The Governor decides to inform UNIT . The Doctor tells the Brigadier to let Lee go . The Brigadier is informed of Jo ' s position . Mailer shouts through the door that they are to be freed or Jo will be killed . The Governor agrees to talk . Barnham arrives in a daze . Jo uses the distraction to disarm Mailer . The guards storm the prison . A fight breaks out . Jo ends up holding Mailer up at gun point and handing him over to the Governor . Later the Master arrives at the prison . The Governor tells of the issues they have been having with the machine and the involvement of UNIT . The Master asks to see Mailer . He is taken to him . Mailer tries to hit the Master but he overpowers him . The Master whispers that he is here to help him . He gives Mailer weapons and says he is going to help him escape . The plan is to overpower the guards and , as soon as possible , make everything look like it is running normally . The Master and Mailer use smoke grenades and guns to escape and take over the prison . Jo , Summers and Barnham are disturbed by the alarm . The Master orders the prisoners to stay in their cells until the fumes have cleared . He puts a blocking device on the phone . Jo is taken hostage by a prisoner . The Master stops the alarm . The Doctor arrives at the prison . The Master , who is now in charge , allows him in . As soon as he is through the gates , Mailer jumps out with a gun . The Doctor is distinctly unphased and allows himself to be led to the Master . The Doctor says that if the Master has hurt Jo he will not fail in taking revenge . The Master pulls a gun and says he needs the Doctor ' s help . The Doctor warns that that machine will kill the Master . The Master does acknowledge it has taken on a mind of its own but that is what he wants the Doctor to remedy whilst he is elsewhere . When the Doctor questions as to what the Master considers more important , the Master says that he intends on stealing the missile that UNIT are moving . Yates contacts the Brigadier to say they intend on driving through the night to get back on schedule . The Master tells the Doctor that he intends in launching the missile , wiping out the Peace Conference and plunging the world into war . The Doctor turns the desk over and runs . The guards try and get him but he eludes them . Jo and Summers hear the gunfire and wonder if the Doctor has arrived . They call for him . The Doctor sneaks back into the prison and hears their calls . He runs into the processing room where he is met by the Master and Mailer . Mailer handcuffs him into the processing chair before he is asked to wait outside . The Master says he has repaired the machine and wants to see how long the Doctor can hold out against it . He takes the amplifier out of the Doctor ' s pocket and switches it round so that the machine can project into his brain . He turns the machine on and leaves . The Doctor struggles to be free as the machine grinds into gear . He sees a Dalek looming towards him . Episode four . The prisoners moan , clutching their ears and hear the moaning sound . The Master is also affected and goes to the Processing Room . He struggles to the machine and switches it off . He checks on the Doctor . Only one of his hearts are beating . He tries to kick start his other heart . A prisoner comes to get Summers . He objects but is forced . Jo is told that she is being saved for the machine . The Doctor awakens . The Master tells him that he was within an inch of dying . The Doctor is dispirited and says that no one can control the machine as he knows its secret ; he encloses a creature that feeds on the evil of the mind . The Master considers this nonsense . He tells Mailer to put him in the cell with Jo , telling the Doctor that if he doesn ' t comply Jo will be next . Mailer helps the Doctor to the cell . He tries to fight with him but is too weak . He is thrown in the cell where he falls to the ground . Jo rushes to get water . The Master presents himself to her . He implores her to talk some sense into the Doctor before leaving and ordering the cell to be constantly guarded . He tells Mailer to clear everybody out of the wing apart from the Doctor and Jo . Once the Master leaves , Jo calls for help urgently . The guard enters and Jo begs him to get Doctor Summers . The machine is reading high . The Master insists that the machine cannot harm him as he is stronger than it . He brought it here and gave it the minds it needed . He is overpowered by the machine and fails to be able to switch it off . He sees the Doctor looming above him laughing . He runs out the room and bolts the door . He says he will give the machine no more minds until it complies . Summers has been brought to the cell . He remarks that the Doctor ' s biology is extraordinary and not human but he has sustained physical and mental shock and is in some form of coma . He can offer no help apart from some tablets he should take if he awakens . He is led away . Jo tries to give a semi - conscious Doctor the medicine but he refuses saying he has the wrong metabolism and that it would probably kill him . He falls unconscious again . Jo weeps . The Master is exhausted . Mailer enters and he pretends all is well . The Master orders him to guard the Processing Room at all times . Mailer asks why they are not escaping . The Master explains they would be caught by the police or the army but he has a plan which will get them all a free pardon , unlimited money and a ticket to anywhere in the world . He shows Mailer a projection of the missile and explains that Mailer and the prisoners are to hijack it . Once he has it he will aim it at the Peace Conference . The Master shows Mailer a map of where they are going to intercept it . A guard enters the cell . The Doctor is still unconscious . Jo asks for food . As soon as they are alone , the Doctor jumps up and thanks Jo . The Master gives the prisoners their orders and they set off . The food comes and Jo knocks the tray into the face of the guard before karate chopping him in the back of the neck . When the other guard enters , the Doctor strikes him over the head with the tray and they escape , locking both guards into the cell . They run into the Master ' s office . Jo sees that a search party is already being formed outside . The Doctor says that they will be expecting them to make a break for it but he intends on laying low for a while . Jo turns on the projector and sees the missile . The Doctor tells her of the Master ' s plan . The prisoners are in place . They see the missile and perform the ambush . A roadblock is created . Yates contacts the UNIT headquarters but a gunshot incapacitates him . The Brigadier receives the message but there is no further response . Yates regains consciousness and sees the prisoners taking the missile . He runs to a motorbike and pursues them . The Brigadier has figured out where the missile was hijacked and heads off there by helicopter . Mailer unloads the missile into a warehouse - watched all the time by Yates . He is spotted and tries to escape but falls off his bike . The prisoners take him captive . The Brigadier is talking to an injured Benton at the scene of the ambush . He sees that both Yates and a bike is missing so realises that he may have pursued . Benton says he recollects seeing a black van like the police use . The Brigadier consults a map and says it probably came from Strangmoor . The Doctor and Jo are still waiting but the Doctor is eager to go and deal with the creature . He describes it as a mind parasite that feeds in evil and is the deadliest threat on humanity since the beginning of time . Jo sees the Master leaving . The Doctor sees his chance to get to the Processing Room and deal with the machine . Inside the Processing Room the machine disappears . A prisoner is looking for the Doctor when the machine appears in one of the cells he is searching in . The prisoner is affected by the machine and then dies . The machine disappears . The Doctor and Jo find the prisoner and note that he looks terrified . The Doctor speculates that the creature has learnt to move . They go to the Processing Room and find the machine gone . Mailer and another prisoner enter and hold the Doctor and Jo at gunpoint . The machine appears behind them . The Doctor and Jo hide . The prisoner is killed and the machine disappears . The Doctor and Jo emerge but the machine appears directly in front of them . Episode five . The machine disappears . The Doctor suggests that it followed Mailer as he had a higher concentration of evil . The Doctor and Jo find Barnham outside and they all leave together . The Brigadier is in a helicopter above the prison looking for the missile . He sees no sign of it but will continue to look . Jo sees the helicopter and they try and get its attention but they are found by a prisoner . Barnham fights with the prisoner but the Doctor uses Venusian Karate to get Barnham off of him . They are soon surrounded by prisoners . The Master and Mailer argue over the phone . The Master says that it is Mailer ' s fault that Yates followed them . Mailer wants the Master to come back to deal with the machine but he refuses to leave . Mailer says that if he doesn ' t come back , Mailer and the prisoners will leave and tell the world about the Master ' s plans . The Master agrees to come back . Once he hangs up the phone he tells Yates to stop feigning unconsciousness and tells him his plan . He explains that he is a hostage in case anything goes wrong and leaves him alone . The prisoners present the Doctor , Jo and Barnham to Mailer . Mailer refuses to talk to Barnham . Mailer pulls a gun on the Doctor . The Doctor asks why Mailer is working with the Master . Mailer tells of the promises that the Master has made . The Doctor and Jo say that the Master won ' t deliver . Mailer asks if the Doctor can make him a better offer . When he says he can ' t , Mailer sends them back to the cells . The Brigadier tells Major Cosgrove that he considers the missile to be in the prison . Cosgrove wants to attack but the Brigadier says the prison used to be a fortress and that they wouldn ' t be able to get in . Cosgrove asks if there was a secret underground passage . They check a map and find one . They are interrupted by report of a car containing the Master entering the prison . The Brigadier says they will use the secret passage and a Trojan Horse to gain entry to the prison . The Master presents himself to the Doctor and Jo . They are playing checkers and keep him waiting until the game is complete . The Doctor refuses to control the machine and says he has no reason to help the Master . The Master says that it would save lives . The Doctor counters that it would be the lives of his mercenaries . The Master says that the Doctor has misunderstood him and tells him that Mailer will shoot Jo if he doesn ' t comply . Forced into helping the Doctor says that he does have a theory that might inhibit the machine . He is lead away whilst Jo remains in the cell . The Brigadier briefs his men about the plan . Benton returns after discharging himself from hospital . He wants to come on the assault . The Brigadier eventually agrees . He asks after Yates and the Brigadier has to admit they have heard no news . Yates has freed himself from his binds . A guard comes to check on him . Yates overpowers him , steals his gun and escapes . The Master begs the Doctor to hurry . The Doctor explains his plan is to put a metal coil connected to a device of his own creation around the machine . When the device is switched on it will create a fake impulse similar to the human brain which will confuse the machine and render it in one place . The Doctor goes in with the coil . The machine senses him and as he approaches the coil bursts into flames . The Doctor sees visions of the Daleks . He manages to put the coil around the machine and shouts to the Master to turn the device on . The visions stop . The Master calls for Mailer before he congratulates the Doctor . The Doctor warns it will not hold the machine for long . The Doctor is returned to his cell where he tells Jo of what he has done . They share scraps of food they find on the floor and drink water as the Doctor tells Jo of the time he was trapped in the Tower of London with Walter Raleigh . A truck approaches the prison . The Brigadier , disguised as a workman , alights and rings the bell . Three UNIT soldiers emerge unseen from the back and stand behind the truck . The Brigadier says he has provisions for the prison . The prisoner tries to send him round the back but the Brigadier says his truck won ' t fit . The prisoner tries to send them away but the Brigadier says it will look strange if that was the case . The prisoner radios for guidance and it is agreed they can come in . The soldiers follow the van in and disable the two prisoners on the gate . UNIT Ambush the prison . The Brigadier announces through a megaphone that the prison is now in military hands . The Doctor and Jo listen and hope that UNIT are swift before they start killing hostages . There is a protracted firefight between UNIT and the prisoners . Many of the prisoners are killed . The Brigadier goes off to find the Doctor as more UNIT soldiers enter . Mailer enters the cell and says he wants to use the Doctor and Jo as a human shield to get out of the prison . The Doctor leads the way then Jo then Mailer . As they go down some stairs , Jo falls backwards onto Mailer . Mailer grabs hold of her and points his gun at the Doctor . A gunshot resounds through the prison . Episode six . The shot was from the Brigadier ' s gun and Mailer slumps forwards - dead . Benton tells the Brigadier that the Master got away . The Doctor tells the Brigadier that the missile is not in the prison and then questions how well he is doing . The Master arrives at the hangar and begins to direct the missile . UNIT have managed to get the prison back under control . A soldier says they found Barnham hiding and Jo stops them from locking him up with the other prisoners . The Doctor explains how Barnham came to be like he is . They begin to consult a man when Yates radioes through from the mobile HQ . He tells the Brigadier where the missile is and the Brigadier says he will come out to meet him . The coil around the machine begins to pop and smoke . The Brigadier leaves Benton in charge of the prison . He bids goodbye to the Doctor in an arrogant manner but the Doctor warns him that all might not be as straightforward as he envisages . He tells the Brigadier he intends on staying here to destroy the machine . The machine tries to move . The coil bursts into flames . The controls set alight . Finally the machine moves in front of two guards and kills them . The Doctor has finished his plan . He heads off with Jo in tow . Summers calls to ask Benton about some medical supplies . Benton barks at Barnham for interfering and Barnham slopes off . The Doctor and Jo find the guards . The Doctor says the machine has stored up all its energy and blown the circuits , meaning that it ' s stronger than ever . Barnham wanders by as the machine appears . Jo and the Doctor are effected but as Barnham wanders in the machine stops . Barnham recollects the room and runs out which causes the machine to start again . The Doctor grabs Barnham and forces him to the machine . He realises that the goodness in Barnham ' s brain neutralises the machine . The Brigadier arrives at the mobile HQ . Cosgrove tells him that the missile has an abort process that can be controlled remotely . The Doctor has unearthed the creature that lives inside the machine . Jo wants him to destroy it but the Doctor says that only an atomic explosion or an enormous charge of electricity can kill it . The Doctor goes to see Benton and asks him to arrange for a cable and a power boost from the National Grid . The phone rings . It is the Master . He asks if the tables have been turned . Summers enters and orders Barnham back to the hospital . He drags him away and the machine starts again . Jo drags him back . The Master tells the Doctor that he still intends to fire the missile to begin World War Three , render the planet in ruins and then emerge as the leader . The Doctor suggests a deal . He will give the Master the dematerialisation circuit for his TARDIS if he hands over the missile . The Master agrees and says that just those two should be present at the hand over . As soon as the Master hangs up the Doctor tells Benton to contact the Brigadier and cancel the attack . Summers is convinced to leave Barnham with Jo . The Doctor tells the Brigadier of his plan . The Brigadier says he has other plans up his sleeve . The Brigadier tells Cosgrove to stay on the line to missile control and tells Yates to clear the area around the hangar . Jo doesn ' t understand why the Doctor is so anxious . The Doctor doesn ' t want to give the Master the circuit and allow him to escape and cause damage to other planets . All of a sudden the Doctor comes up with a plan which means both the Master and the machine will be destroyed . The Master flicks a switch on the console and takes out a circuit . Barnham picks up the machine and is lead away . The Brigadier tells the Doctor that they can ' t explode the missile manually . The Doctor says that the Master would obviously disconnect the abort circuit . The Brigadier says that they have no choice but to give the Master back his dematerialisation circuit . The Doctor is still concerned and says he has another plan . Jo and Barnham are driven to the hangar in a police van by the Doctor . The Master pulls a gun as the Doctor emerges . The Doctor distracts the Master as Barnham and Jo sneak out the back . The Doctor and the Master have a stand off about the handing over of the circuit . Suddenly the Doctor uses Venusian Karate to knock the Master to the ground . Barnham drops the machine by him and all three run causing the machine to effect the Master . Jo contacts the Brigadier whilst the Doctor goes to look at the console . He repairs the abort circuit as a helicopter lands . As they run to the helicopter , Barnham stops to help the Master . The machine stops and the Master knocks Barnham down and runs him over in the police van in his effort to escape . The Doctor and Jo run back to check on him . He is dead . They escape in the helicopter . As the hangar explodes , Jo looks on in tears . Back at the Governor ' s office , Jo and the Doctor mourn Barnham ' s death . The Brigadier urges them to be thankful that they at least managed to rid the Earth of the machine and the Master . The Doctor isn ' t convinced that the Master is gone , but the Brigadier is confident that even if he wasn ' t killed in the explosion , he wouldn ' t get very far without his dematerialisation circuit . The Doctor begins to agree , only to realise that he no longer has the circuit on his person . While the group is wondering what became of it , the phone rings . Benton answers it , and hands it over to the Doctor saying it ' s the Master calling . The Master gloats that he is alive and well , much to the Doctor ' s frustration . He adds that , thanks to the Doctor , his TARDIS is now working once again , and that they won ' t be seeing each other for quite some time . The Master vows he will one day return to destroy the Earth , and the Doctor along with it . As a final insult , he tells the Doctor to " enjoy his exile . " Jo tries to lift the Doctor ' s spirits by reminding him he won , but to no avail . The Doctor is annoyed that the Master is free to come and go as he pleases , while he is stuck on Earth with the Brigadier . The Brigadier grins at that last remark . Story notes . Filming locations . Location filming took place in - Home video and audio releases . Digital releases . This story is available :