The Android Invasion ( TV story ) The Android Invasion was the fourth story of season 13 of " Doctor Who " . It saw the final appearances of John Benton and Harry Sullivan in the classic series . Synopsis . The Fourth Doctor and Sarah find themselves in the English village of Devesham near a Space Defence Station . The village seems deserted , the telephones don ' t work , calendars are stuck on the same date and white - suited figures are wandering about aimlessly . Who are the Kraal s and what are their plans for Earth ? Plot . Part 1 . A UNIT soldier walks , as if in a trance , through the woods , his right arm twitching spasmodically . Nearby , the TARDIS materialises . The Doctor and Sarah step out . The Doctor explains that the coordinates were set for Sarah ' s time , but the linear coordinates were off . They could be miles from London . In any case , Sarah is glad to be back on Earth . The Doctor detects an odd reading of energy or radiation nearby . The Doctor and Sarah meet four figures in white overalls and helmets with dark - tinted visors . When the Doctor asks them for directions , they shoot at the travellers with their index fingers . The Doctor and Sarah duck and run , with the four in pursuit . Sarah slips down a hillside and clings to a cliff ledge . The Doctor helps her up . They see the soldier , jerkily making his way towards the cliff ' s edge . The Doctor shouts at him to stop , but he pays no heed . He runs over the cliff and falls to his death . The Doctor searches the body . He finds a wallet full of shiny , freshly minted coin s , all dated the same year . They also spot a casket - shaped pod nearby , which the Doctor finds familiar . Before he can identify it , shots ring out . The white - suited men have found them again . He and Sarah run again , avoiding their pursuers . They reach a village which Sarah recognises as Devesham . It lies about a mile from a Space Defence Station . The village , however , is deathly quiet and seems empty . The Doctor decides to try the local pub , the " Fleur - de - Lys " , but it too is empty , and the Doctor finds the same freshly minted coins in the register . Sarah spots the white - overalled figures coming down the street , accompanied by the " dead " soldier . A large pickup truck arrives , carrying what seem to be villagers , all in trances . They are helped off the vehicle by the white - overalled figures and distribute themselves around the village . Mr Morgan , the landlord of the pub , enters it with several other people while Sarah and the Doctor hide in the store room . The villagers take their seats silently , waiting motionless until the clock strikes eight , whereupon they suddenly come to life , acting normally . The Doctor intends to get to the Space Defence Station and contact UNIT . He leaves , telling Sarah to meet him at the TARDIS if anything goes wrong . However , the " dead " soldier finds her in the store room and questions her . Morgan suggests that Sarah might be part of " the test " . When Sarah asks what test , he tells Sarah that she should go . Outside , Sarah hides behind the truck . She observes one of the white - overalled figures standing near the vehicle turn around . Its helmet visor is raised , but beneath is nothing but plastic and electronics . Sarah runs for the woods , reaching the TARDIS . She spots a similar pod next to the time machine and goes to examine it , leaving the TARDIS key in the lock . Suddenly , the TARDIS dematerialises . As Sarah is still trying to understand why , a hand reaches out from the pod . Startled , Sarah sees a man lying inside . When she goes closer , he grabs her by the throat . She breaks free and runs . At the Defence Station , the Doctor asks a soldier where the commanding officer is . The soldier just stares ahead , unresponsive . Also inside the building , Senior Defence Astronaut Guy Crayford is addressed by a disembodied voice . The voice , named Styggron , tells him there is a random " unit " within the complex and orders him to check . The Doctor enters an office marked Brigadier Lethbridge - Stewart . It is empty . Crayford enters and points a gun at him . The Doctor introduces himself as UNIT ' s scientific advisor . Crayford has heard of him , but as the Brigadier is in Geneva , and Colonel Faraday is in command , there is no one to confirm the Doctor ' s identity ; he could be an impostor . Before Crayford can have the Doctor taken to detention , the Doctor flips the desk over and runs . He makes it outside before he is recaptured . Sarah sees this and sneaks into the building . She goes to the Doctor ' s cell and unlocks the door , unaware that from behind a wall a stony alien face is observing them . Part 2 . Styggron contacts Crayford again , complaining about a second random unit . Crayford identifies these random units as the Doctor and Sarah . The alarm sounds , indicating the Doctor ' s escape . Crayford sends his UNIT soldiers to stop them . Hiding in a storage cupboard , the Doctor tells Sarah about Crayford . She says it is impossible . Crayford was in deep space testing the XK - 5 space freighter when it vanished , presumed to be destroyed . The Doctor and Sarah venture out to find Sergeant Benton standing in the reception area . He points a pistol at them . Styggron wants the Doctor captured alive . When Crayford cancels the kill order , Benton seems to be dizzy , giving the Doctor and Sarah a chance to run away . Crayford orders Harry Sullivan to cordon off the perimeter road . The Doctor and Sarah decide to return to the village and warn London . They are pursued by tracker dogs . Sarah twists her ankle in the woods , and this slows her down . The Doctor hides her in a tree , taking her scarf to draw the dogs away . He hides by submerging himself in a pond and the dogs lose his trail . Unfortunately , when the soldiers turn back , they spot Sarah and capture her . Styggron tells Crayford to locate , but not seize , the Doctor . He has other plans for him . Meanwhile , in an alien - looking room , Sarah is strapped to a table . Harry tells her it is no use to struggle . Under Styggron ' s order , he starts the scan . In the village , the Doctor finds the telephone s are not working . He meets Morgan , who tells him the lines are down after a gale . Styggron speaks to another of his kind , Chedaki , who feels the time for experiments are over . Styggron insists that they must confirm their techniques as flawless if they are to conquer worlds other than Earth . Styggron contacts Crayford and tells him to commence the final test . In the pub , the Doctor finds more oddities : an unused dart board , plastic horse brass on the wall and a tear - off calendar with only one date . The telephone rings , and Morgan answers it . The call is for the Doctor . It is Sarah , who tells him she was captured but escaped . She asks the Doctor to meet her by the village shop and to be careful of the robot s . He hangs up and finds that the telephone has stopped working again . The Doctor meets Sarah , who explains how she escaped . The Doctor remarks on the providence of her finding the only telephone in the village that worked . He believes they are being tested to find out how smart they are . He decides to take Sarah to the TARDIS and use the radio there . However , the TARDIS is gone . The Doctor is puzzled : the ship is not programmed to auto - operate , unless . . . he asks Sarah for her TARDIS key . When she claims she has lost it , the Doctor tells her she never had it . When Sarah put the key in the lock , she released the TARDIS ' pause control , and it continued its journey to Earth . This is not Earth , this is not a real forest , and she is not the real Sarah . The Doctor grabs the duplicate by the shoulders and demands to know where Sarah is . The duplicate pulls free but falls to the ground , her face popping open to reveal the electronics underneath . Part 3 . The android Sarah rises to its feet and fires its pistol at the Doctor ' s retreating form . Chedaki tells Styggron it was a foolish experiment . The Doctor could undo their plans . Styggron dismisses this . The village and the Doctor will be destroyed by a matter - dissolving bomb . The real Sarah is being kept alive so Styggron can test the virus he intends to use to cleanse the Earth of human life . All the while , Sarah is feigning unconsciousness and listening . When the coast is clear , she gets up and sneaks away . The Doctor watches the truck drive into the village and evacuate the androids to the Kraal base . The Doctor is grabbed from behind by Styggron , who gets two of the white - overalled figures to tie him up while the Kraal places the bomb at the Doctor ' s feet . Luckily , Sarah has made it back to the village . She uses the Doctor ' s sonic screwdriver to cut his bonds . They run into the base and shut the door as the village dissolves into a wasteland . However , the two are surrounded by androids , who escort them to a cell . The Doctor tells Sarah that he should have realised — the radiation levels he picked up when they landed were those of Oseidon , the Kraal planet . The levels are increasing , and the planet will soon be uninhabitable . This is why the Kraals are invading Earth . The duplicated village and their androids are a training ground . Crayford enters the cell and tells the Doctor that it is all for the best . Soon , the Kraals will send his ship back by space - time warp so he can make a normal landing . He has recently established radio contact with Earth . He fed them a story of how his ship was trapped in an orbit around Jupiter and he survived by rationing his supplies and recycling his water . With the world ' s attention focused on his landing , the space shells containing the androids will be taken for meteorite s . The androids will emerge and pave the way for the main invasion fleet . He is helping the Kraals because , while Earth left him for dead , the Kraals rescued his ship and rebuilt his body . The Kraals only want to survive and have also promised him no humans will be harmed as long as they obey . Styggron gets " Harry " to place a drop of the virus in a jug of water to be taken to the cell . Meanwhile , although the sonic screwdriver is useless on the door , the Doctor has removed a floor plate . He intends to use the wiring below to electrocute their android guard . " Harry " enters with the water and to take the Doctor away . Before the Doctor goes , he tells Sarah not to waste the water . The Doctor is strapped to the Kraal analysis table . It will copy all his knowledge and experience . Despite what Styggron has told Crayford , he reveals he " does " intend genocide . Earth ' s resources are too limited to be wasted on an " inferior species " . The virus , distributed by androids , will wipe the Earth clean in three weeks , then burn itself out . Styggron will signal the invasion fleet . Styggron leaves the machine to do its work . When it finishes , the stimulation will make the Doctor ' s head explode . Sarah rigs the wiring beneath the cell floor and sets a small fire to lure the android guard . He steps in the puddle of water and is electrocuted when Sarah applies the power cable . She makes her way to the Doctor and turns off the scan . She helps the disorientated Time Lord out of the base , heading for Crayford ' s rocket before it takes off . The rocket is launched , and the G - forces start to crush them . Part 4 . Sarah blacks out but is awakened by the Doctor . He tells her that was nothing ; there is a more dangerous ride ahead . Before the rocket lands , the pods will be ejected . The Doctor and Sarah will ride two of them to Earth to warn the real Defence Station . He cannot guarantee they will survive the trip . As they talk , neither notices a nearby pod open to reveal an android Doctor . On Earth , Matthews at the Defence Station ' s scanner room picks up Crayford ' s rocket . Grierson , the man in charge , informs Colonel Faraday . Meanwhile , having found the TARDIS in the woods near Devesham , Benton and Harry have been searching for the Doctor and Sarah , to no avail . Benton is worried . He has never known the Doctor to leave the TARDIS key in its lock . Faraday welcomes Crayford home on the radio , but the signal is broken up by the " meteor shower " of pods . Unusually , they slow as they enter the atmosphere . Some of the pods land in a nearby field . One opens up to reveal the Doctor . However , he is unable to find Sarah . Sarah , having landed elsewhere , finds the TARDIS in the woods . As she looks around , the Doctor taps her on the shoulder . However , this Doctor is an android . Behind it , a pod opens to disgorge another Sarah replica . The real Sarah runs for it . The XK - 5 re - establishes contact and comes in for a landing . Harry and Faraday head for the rocket , not knowing that Styggron is there with Crayford . The real Doctor enters the station and recognises the " dead " soldier . The Doctor shows him a pass and tells him that if he sees the Doctor again today , he is to report it to him immediately . The Doctor goes to the scanner room , leaving the soldier puzzled . When Benton tells him where Harry and Faraday are , the Doctor contacts them on the radio and urges them not to enter the rocket . He will meet them at the lift . While the Doctor gives Grierson instructions for modifying the radar dish , an android Matthews has incapacitated Benton and introduced an android replacement . Grierson says that if the Doctor points the dishes down here , it will jam every piece of electronic equipment for miles . Faraday returns to the scanner room , demanding an explanation . The Doctor tells them about the Kraal invasion . However , he is too late : Harry and Faraday have been replaced , and the android Doctor is pointing a gun at him . He slams the door in the android ' s face and leaps through a window . Outside , he meets Sarah . The Doctor tells Sarah their only chance is to stop the androids before they take over the complex . He runs back towards the scanner room , bluffing his way past " Benton " by posing as his duplicate . Sarah climbs up the rocket towards the real Harry and Styggron . Grierson finishes his modifications but is shot in the shoulder by the android Doctor before he can turn on the power . The android is about to shoot the original when Crayford enters , saying Styggron promised no killing . The " Doctor " calls him a fool and tells him about the virus . Crayford cannot believe this , but the real Doctor tells him that his rocket was actually hijacked by the Kraal . They did not reconstruct him , they brainwashed him . Realising the truth , Crayford rushes out , distracting the android long enough for the Doctor to make his move . In the struggle , the Doctor activates the radar , jamming all the androids in mid - step . In the rocket , Sarah unties Harry and Faraday . Styggron enters , holding a ray gun on them , but Crayford appears and attacks him . The two grapple , and Styggron shoots Crayford . The Doctor makes his own entrance , punching the Kraal , who falls on the vial of virus , cracking it open . Styggron shoots the Doctor before he dies . Sarah is horrified , but the real Doctor shows up — he had programmed his duplicate to distract Styggron . The android disintegrates into its component parts . Sarah and the Doctor make their way back to the TARDIS . Sarah says she is going to take a taxi home , but when the Doctor offers to take her home instead , she smiles , " How can I refuse ? " They enter the ship , and it vanishes . Home video and audio releases . DVD releases . " The Android Invasion " was released on DVD on 9th January 2012 in the " U . N . I . T Files " Boxset with " Invasion of the Dinosaurs " . Its contents include : Video releases . This story was released on VHS in the United Kingdom and Australia in 1995 and the US in 1996 .