Paradise Towers ( TV story ) Paradise Towers was the second story of Season 24 of " Doctor Who " . After a much - publicised falling out with Eric Saward , John Nathan - Turner was keen to find a writer who hadn ' t worked on the show before . At the BBC ' s script unit , he met Stephen Wyatt and asked him to submit a script for " Doctor Who " . At first the script lacked a traditional " monster " . The robotic Cleaner s were added to the script to fulfil this role . Synopsis . The Doctor and Mel decide to visit Paradise Towers , a residential complex that promises a peaceful life to its residents . However , the establishment is far from what its name suggests . A conflict persists among the Kangs , humanesque , multicolour beings who gather in opposing gangs based on which colour of the rainbow they bear . Furthermore , killer cleaning robots prowl the halls , and a secret in the complex ' s basement poses the greatest threat of all Plot . Part one . The last remaining Yellow Kang hides from the jeers of the other Kangs in a corridor , while the voices of her pursuers announce they have given up looking . Relieved , she turns to find something bearing down on her and screams . In the TARDIS , Mel looks longingly at the swimming pool displayed on the TARDIS scanner . They ' ve arrived at Paradise Towers and Mel is looking forward to taking a dip . However , upon leaving the TARDIS , they find the place in disarray . The surfaces are filthy and rats scuttle around underfoot . Caretaker 345 / 12 , subsection 3 reports in to the Chief Caretaker , telling him he has found evidence of " wallscrawler s " on Potassium Street . As he continues his inspection , he finds a bloodied rag . Meanwhile , the Doctor and Mel find themselves threatened by a group of teenage girls calling themselves the Red Kang s . The Doctor placates them and they take a liking to him . Two of their number introduce themselves as Fire Escape and Bin Liner . They tell the Doctor they are rivals of the Blue Kang s and the Yellow Kang s , though only one of the latter is still alive . A Blue Kang is following Caretaker 345 / 12 , subsection 3 and uses a telephone to report that the Yellow Kangs are no more . After she leaves , a robot drives past with the leg of the last Yellow Kang sticking out of a rubbish container behind it . Back with the Red Kangs , the Doctor is asking questions . He finds that there are three types of people present in Paradise Towers : the Kang s , the old ones and the Caretakers . There seems to be more , but before Fire Escape can tell the Doctor of this group , Bin Liner gestures to her with a warning to keep silent regarding such things . With that they take the Doctor and Mel captive , having become interested in them after hearing their conversation about " the pool in the sky " . Caretaker 345 / 12 , subsection 3 finds himself facing one of the robots , with a second sneaking up behind him . He gets through to the chief , who tells him not to panic . One of the robot grabs him with a mechanical claw and kills him . The Caretaker watches on a screen as the robot takes the body away . He puts out a message for all Caretakers to seize every " red wallscrawler " in Fountain of Happiness Square . As the Red Kangs are taking Mel and the Doctor to a new location , the Caretakers move in . The group flees but the Doctor falls and is taken prisoner . Separated from the Doctor and the Red Kangs , Mel comes across Tilda and her friend Tabby and is welcomed into their home . There are large bones on the table which are tidied away before they let Mel enter the room . Mel asks them what group they belong to and they tell her they ' re Rezzie s . They ply Mel with tea and cake s and invite her to dine . The Doctor is being escorted by the Caretakers , including the Deputy Chief Caretaker , who allow him a short rest . He finds a " wallscrawl " depicting a Kang being attacked by a mechanical claw , with other mechanical objects surrounding this centrepiece . The Deputy shrugs it off as made - up imagery . One of the robots turns the corner as they chat and the Doctor identifies it as " some sort of robotic Cleaner " . As it readies its claw , they run away from it . Back in Tilda and Tabby ' s house , Mel is encouraged to stay awhile and eat to her heart ' s content . Just as Tabby comments on the peacefulness of her home , the door is broken open and a man steps in , asking if Mel is either in or causing trouble . When he finds she is not , he introduces himself as Pex , telling her he " puts the world of Paradise Towers to rights " . Mel stands amazed at his immodesty . Elsewhere , the Doctor and his Caretaker accompaniment escape the Cleaner by taking a lift . Mel decides to leave Tilda and Tabby . Once outside , Pex tells her he will be her guide and help her find the Doctor . They come across some Blue Kangs engaged in worship . Meanwhile , the Doctor is brought before the Chief Caretaker who takes him for the original architect of Paradise Towers . The Deputy asks what is to be done with him and the Chief orders that the Doctor should be killed . Part two . The Doctor tries to convince the Chief that he is not the " Great Architect " , but to no avail . The Chief orders his deputy to organise the execution . He gets a phone call from Caretaker 579 / 14 , subsection 8 , about the death of 345 / 12 , subsection 3 , and is required elsewhere . Until his return , the sentence is postponed . Elsewhere , Mel and Pex are still looking for the Doctor , and the Red Kangs find one of their number , No Exit , has been killed by the Cleaners . The Deputy and another Caretaker are guarding the Doctor . He asks to see the rulebook by which they run their lives and they oblige , treating it as his last request . Pretending he is reading rules from the book , the Doctor tells them to step away from him , close their eyes and put their hands on their heads . They do so and he takes the key card from the Deputy and escapes . Mel and Pex narrowly miss the Doctor . They find themselves back at the Fountain of Happiness Square . Mel asks Pex who he really is and he replies he had power invested in him by those he cannot name . As they move out of the square , they are followed by the Blue Kangs . The Doctor comes across a wallscrawl while looking for Mel , takes out pen and paper and makes notes . Elsewhere , the Chief Caretaker is reassuring his team . He tries to quell any fears they have that the Caretakers are responsible . In their home , Tabby and Tilda are visited by Maddy , who tells them about the death of yet another Caretaker . She tells them that people cannot simply be disappearing and they agree , covering up their dinner . Meanwhile , the Doctor comes across a telephone and breaks it . Money floods out . As he collects it in his hat , two Cleaners move in on him and he is forced down a hole . He wakes to find himself in the Red Kangs ' " brainquarters " . He confronts them about the Cleaners , but they know less than he , nor do they know what the creature their own wallscrawls depict is . The Doctor tries to use another phone , but it is not in use . He turns the cabinet attached to it around to reveal that it is a vending machine . He buys a can of Fizzade and shares it out amongst the Kangs . The Chief Caretaker visits the creature . He refers to it as " my pet " and himself as its " daddy " . He asks the creature if it enjoyed its Caretaker snack and asks it who else has been feeding it . It replies that it is hungry . The Chief leaves , promising to feed it the Great Architect . Meanwhile , Mel and Pex find themselves prisoners of the Blue Kangs . Mel asks them if they know who Pex is and they tell her he ' s the " musclebrain " , an inbetween — a term for those who are middle aged — who went with the Kangs by hiding aboard their ship , rather than fight in a war with all the other inbetweens . Mel is allowed to leave . The Kangs call Pex a " scaredy - cat " . The Chief declares it is time to seek the Great Architect and teach the Kangs a lesson for their recent defiance of Caretaker authority . Elsewhere , Mel finds herself back in Tilda and Tabby ' s company when she is invited in for tea . In their brainquarters , the Red Kangs are all drinking Fizzade now . The Doctor tries to side with them . However , an alarm blares and Bin Liner warns the Caretakers are moving in . On the other side of the door , the Caretakers begin to break it down . Back in their house , Tabby and Tilda are having crumpets with Mel , but this time , they have no intention of letting her go . They throw a net over Mel and Tabby brandishes a toasting fork at her throat . Part three . The Doctor buys the Red Kangs time and encourages them to make their escape . Meanwhile , a tied up Mel warns Tabby that there is something wrong with the waste disposal unit . As she inspects it , a claw bursts out of it , grabs Tabby and pulls her through . Tilda blames Mel and brandishes a knife at her . Pex bursts through the door , Tilda throws a knife at him but misses and runs to get another knife , but as she does so , the claw again emerges and pulls her through too . In the corridor , a cleaner drives past with Tilda ' s foot sticking out of it . The Caretakers break down the door to the Red Kang brainquarters to capture the Doctor . They find that he is the only one there . Mel is still trying to get to the " pool in the sky " — as it is known locally — where she arranged to meet the Doctor . Pex warns her that only the " un - alive " go there but deems it his duty to accompany her . The Doctor is brought before the Chief Caretaker , who deems it necessary for them to have a chat . The Deputy queries his leader as to the recent Caretaker fatalities , breaking several regulations and resulting in him being sent out of the room . The Chief tells the Doctor the " Great Architect " disappeared under mysterious circumstances soon after the completion of Paradise Towers . News of Tilda and Tabby ' s deaths draws the Chief away and he leaves the Deputy to once again guard the Doctor . Elsewhere , Mel and Pex enter a lift with a cleaner bearing down on them . The Kangs had pressed the buttons in the lift so Mel and Pex are constantly moving and stuck in the lift . Bin Liner and Fire Escape break into the Chief ' s office and tie up all the guards freeing the Doctor . In Tilda and Tabby ' s flat , the Chief is interviewing Maddy . He tells her there is no cause for alarm and encourages her to keep news of the incident quiet . She does not want to do so , but the Chief offers her the flat — which is much larger than hers — and she agrees to say nothing . In the lift , Mel and Pex are stuck moving up and down between floors 173 and 174 . Pex tries to fix the controls , but only causes the lift to quickly descend . They find themselves in the basement and hear a voice saying , " Soon , soon I shall be free " . In the Red Kang brainquarters , the Doctor is watching an information video about Kroagnon , the " Great Architect " . He tells the Kangs of Miracle City , a place built by Kroagnon and from which he refused to move out , or let anyone in . Eventually he was forced out and those who moved in he killed . However , nothing could be proven and so he walked free . Pex gets the lift working again , and they start ascending . The Chief finds himself facing cleaner 479 , who forces him to follow . At the brainquarters , the Doctor convinces the Red Kangs they must go the basement . The Blue Kangs burst in and proclaim victory over the Reds . The Doctor tries to convince them there is no time for games and they must all work together . Mel and Pex arrive at Floor 304 to find a serene , clean area of Paradise Towers greeting them . Mel finds the pool and settles down to rest in preparation for her swim , despite Pex thinking the water is dangerous . For once , his thoughts are correct . In the water , a giant , yellow , mechanical crab - like cleaner lurks below the surface and sights Mel on the edge . The Chief is brought before " his pet " by a cleaner and asks him why he has been killing so many people . He replies that he needed a body to live in , but the ones the cleaners brought were not satisfactory . Behind the Chief , the Doctor , Bin Liner , Fire Escape and Drinking Fountain are sneaking up on them . The Chief is forced into a container as the creature declares itself as Kroagnon . The cleaners attack the Doctor and his friends and a cleaner grabs the Doctor with its claw and begins to throttle him . Part four . The Kangs pull the Doctor free . They all flee . The container the Chief was placed in rises , leaving a silver - clothed Chief in its wake . Kroagnon has taken his body and reveals he tried to stop the use of Paradise Towers , leading to his imprisonment . He declares that , with the cleaners , he will destroy everyone in the Towers . The Doctor and the Kangs stop to rest with the immediate danger gone . He thinks the parents of Paradise Towers ' current inhabitants must have imprisoned Kroagnon , but he devised a means to perform corpoelectroscopy - a way to transplant his brain to a host body . On Floor 304 , Mel is swimming . She encourages Pex to join her but he just sits at the side . Suddenly , the water - bound cleaner surfaces and attacks Mel . In the Red Kang brainquarters , the Blues and the Reds have gathered . They wait for Fire Escape ' s arrival and plan to head for the " pool in the sky " . Back in the pool , Mel urges Pex to help her . She gets into the shallows and , borrowing Pex ' s gun , shoots the cleaner . It sinks below the surface , its casing blown open . In the Chief ' s office , the Deputy puts out Regulation ZZZ - an order for Caretakers to act with extreme caution and return to base . Downstairs , Kroagnon leads a cleaner through the corridors as it spurts out jets of poison ous gas . A nearby Caretaker falls and dies and Kroagnon decides to return later to collect the " rubbish " . Meanwhile , the Doctor and the Kangs join Mel and Pex on Floor 304 . The Kangs start taunting Pex again and he moves to leave , but his way is blocked by three Rezzies - including Maddy - who propose an alliance . Kroagnon enters the Chief ' s office and confronts the Deputy . Realising that he is no longer the Chief Caretaker , the Deputy runs away . After some discussion , the Kangs agree to work with the ( apologetic ) Rezzies and Pex . They claim they will never work with the Caretakers , but , as they do so , the Deputy arrives and joins their alliance . In the Chief Caretaker ' s office , Kroagnon is marking off floors that have been gassed . He notes that everyone will head to Floor 304 and he will gas each floor on the way up . On Floor 304 , the Deputy reveals that on Floor 245 , Sodium Street , corridor 75 , there is a secret emergency supply of explosives kept for pests going out of control . They decide to use this to set a trap for Kroagnon . The Rezzies plan to slow the cleaners with the table cloths they make , while the Kangs destroy them with explosives and the arrow gun s they carry . Back in the Chief ' s office , Kroagnon is still marking off floors as they are gassed . He decides to check what is going on in " the pool zone " , but finds that the surveillance has been prevented by " the Great Architect " . The Doctor outlines his plan to capture Kroagnon : he will offer to meet their enemy . Someone will lead Kroagnon to him , where he will be trapped . Pex offers to do this , to the amusement of the Kangs . In the Chief ' s office , Kroagnon gets a message from the Doctor who criticises his work as an architect . In a corridor , a combined Rezzie and Kang effort sees a cleaner destroyed . On Floor 304 , the Kangs give Pex gifts as he prepares to leave and he gives Mel his gun . Pex goes to the Chief ' s office and uses a video screen to communicate with Kroagnon . He agrees to accompany Pex to the Doctor and they begin to make their way through the corridors . However , contrary to the Doctor ' s order to travel slowly , Pex is fearful of Kroagnon , so they make haste . Soon they meet the Doctor and begin to converse . The Doctor tries to push Kroagnon through a door , but cannot move him . Pex grabs a stick of explosive , pushes the Doctor out of the way and pulls Kroagnon and himself through the doorway . Both are killed in the explosion . The Kangs , Rezzie and Caretakers are holding a ceremony for Pex . They honour his bravery and the Doctor comments that he helped bring them all together . As a parting gift , the Kangs give the Doctor a scarf with a red side and a blue side - making him an honourary Kang . Mel and the Doctor return to the TARDIS and it dematerialises . Behind it , some wallscrawl says " Pex lives " . Continuity . Timeline and location . The Doctor states that Paradise Towers won many awards " way back " in the 21st century . The advanced technology suggests it is set in the latter half ; however , as the Inbetween s had to fight a war ( the Thousand Day War occurs around this time ) , it is unclear how many years passed for the Towers to fall into ruin so the story could take place in the early 22nd century . In " Lucifer Rising " , Bishop had to deal with " the messy consequences of the Kroagnon affair " ( either Miracle City or Paradise Towers ) prior to 2157 . Presumably , the war was on another planet , meaning that humans at this time have space travel ( since " space is a big place " and Kroagnon found other work ) , so the Towers may not have been on Earth ; there is no explanation as to why help never came from the outside world , unless the Towers were simply forgotten . It is also never explained as to whether or not Kroagnon is actually human . Home video and audio releases . VHS . " Paradise Towers " was released onto VHS on the following dates : DVD . " Paradise Towers " was released on Region 2 DVD in July 2011 . It included commentary with Judy Cornwell , Stephen Wyatt and Dick Mills . Other special features were :