Warriors ' Gate ( TV story ) Warriors ' Gate was the fifth story of the 18th season of " Doctor Who " . It saw the departure of Romana II and K9 from the regular cast and concluded the " E - Space trilogy " . The decision was made not to replace K9 with another new model which was the direction taken when Mark I left in " The Invasion of Time " . From a production standpoint , it marked Graeme Harper ' s directorial debut on the programme , although he wasn ' t credited in that capacity for his work . His promotion to the director ' s chair followed one of the rare instances that a director was fired during production of a " Doctor Who " story — although credited director Paul Joyce was quickly re - hired . It was the first episode in which the Doctor started to view Adric as a companion , after the Alzarian had stowed away on the TARDIS . After Romana ' s departure , the Doctor decided not to take Adric home and instead allowed him to carry on travelling , even back to the Doctor ' s own universe . Synopsis . A strange creature forces its way into the TARDIS , steering it to a white void occupied only by the ruins of an old building and a spaceship . This empty space is a gateway to the past and future . The creature responsible for taking them there is Biroc , a member of the enslaved race known as the Tharil . The gateway offers the only exit from E - Space , but the void is contracting . Are the Fourth Doctor and his friends fated to spend eternity in E - Space ? What final shocking revelation awaits the Doctor ? Plot . Part one . A countdown takes place , leading up to the crew of a spacecraft using a Tharil to attempt to escape from “ nowhere ” . They fail . Onboard the TARDIS , the Fourth Doctor is at the controls . They have entered a disruption and the Doctor struggles to make sense of it . The Tharil , Biroc , is taken away but escapes from his escort . He is seen by Lane , who warns the bridge . Meanwhile , the Doctor is trying to land the TARDIS . He moves to press a button but Romana prevents him from doing so because it is dangerous . He considers if he subconsciously wanted to press the button . Romana is still trying to avoid returning to Gallifrey . She asks the Doctor if they have the right to take Adric out of his own time . The Doctor tells her Adric will love it on Gallifrey . Adric decides to press a button and does so , determined by flipping a 100 Imperial s coin , a method suggested by the Doctor . Biroc has escaped the craft and runs through a white void . The TARDIS lands and the console sparks . Smoke pours out of K9 . The Doctor avoids the time wind s coming through the open doors of the TARDIS as Biroc enters and walks to the controls . On the spacecraft , they pick up the TARDIS on their scanners , noting it as a craft . Biroc begins operating the TARDIS controls . The Doctor and Romana note that he is on a different time line , prompting Romana to wonder why he hasn ' t been torn apart . On the craft , Captain Rorvik decides to wake another Tharil up to navigate them out of the “ gap between timelines ” . He announces that they are to go out to the TARDIS . Biroc speaks with the TARDIS crew ; he tells them not to trust Rorvik and his men . He says he ( Biroc ) is a “ shadow of his past , and your future ” to the TARDIS crew , and then he leaves to cross the white void . The Doctor shows Romana the co - ordinates , all zero . He leaves to follow Biroc , after telling K9 to follow him but then realising he has been damaged by the time winds ; he finds a sign of life in K9 and then sets off . Romana tells Adric that they are in the gap between the negative co - ordinates of E - Space and the positive N - Space , which Adric likens to an intersection . The pair set about repairing K9 , who warns them of three approaching humanoids . Using a mass detector , Rorvik and two of his crew search for the craft they picked up . The TARDIS crew see them approaching on their scanner . Biroc arrives at a stone arch with a door in it ; he enters and is closely followed by the Doctor . Inside , Biroc inspects a cobwebbed dining hall . He passes through what appears to be a mirror and disappears . Rorvik ' s group are inspecting the TARDIS . They cannot determine what it is . The Doctor arrives in the dining hall and makes his way around it . He inspects two skeletons in armour , brushing off cobwebs he moves on ; one skeleton moves . The Doctor crouches by the mirror as the skeleton advances on him ; it raises its axe and swings . Part two . The Doctor notices the skeleton attacking him just in time to dodge its axe . A cat and mouse game ensues with the Doctor impersonating a skeleton by keeping still and holding an axe in his hand . However when the Doctor attempts to move away , the skeleton spots him trying to escape and cleaves the axe shaft in two . Meanwhile back on the TARDIS , Romana and Adric are arguing about the trustworthiness of the men from Rorvik ' s crew outside , with Romana deciding to exit the TARDIS and introduce herself to the men , ordering Adric to stay put . They both have a conversation with Romana commenting on the mass detector and Rorvik questioning her on the whereabouts of Biroc , with Romana commenting on the subjectivity of memory . After explaining the problems concerning their ship , Romana then gives a signal on cue signalling danger before being escorted by Rorvik ' s men . After they leave Adric peeks outside the TARDIS doors . In the abandoned building , the Doctor is confronting two skeleton warriors when he points out that he " usually gets along with machines so well " . The Doctor tricks the skeletons into killing each other by staying still and letting them hit each other with their weapons , thus getting himself out of a predicament . Adric and K9 exit the TARDIS against Romana ' s orders to follow her , with K9 experiencing calculation errors due to the damage sustained earlier . Adric tells K9 to stay put and while he is away , K9 manages to restore calculation errors . In the spaceship , Romana is hooked up to navigation equipment exactly like Biroc was earlier , but is initially found ineffective in controlling the navigation equipment . As a result of this failure , Rorvik announces to his crew that they need to bring more Tharils out of hibernation to be navigator , despite his own acknowledgement of the risks involved in their survival . However when an image on the navigation screen is found , the crew decide that Romana is useful as a navigator and leave her in the seat despite the risks . Rorvik decides to exit the spaceship with his crew when one of them can ' t come out due to a leg injury . This however turns out to be a ruse as the same man along with his companion walk normally with the door closing behind them . Back at the building , the Doctor attempts to extract information out the skeletons by tweaking their machinery with a sharp dagger . After a few taps a mechanical voice from the fallen skeleton identifies itself as the " Gundan " whose directive is to " kill the brutes " . It emerges that the Gundans are machines designed by human slaves of the Tharils to fight back against their masters , who fled to safety through the " gateway " . When the Doctor attempts to find out the exact nature of the gateway , the Gundan shuts down from power failure , frustrating the Doctor when the conversation was " just getting interesting " . The Doctor wishes that an alternative power source was nearby when he is surprised by K9 ' s arrival . The Doctor uses K9 to obtain more information from the machine , who reveals that there are three gateways and they are one , implying that although they are different entrances , they have the same exit and that the " masters " came from the gateway . While this is happening Rorvik and his men find the Doctor talking to the machine and just when they were getting very close to finding out the gateway ' s secret , one of the Gundans decapitates the other Gundan and then retreats through a gateway . During the chaos the Doctor escapes with K9 , who is even lower on power supply , and when the crew catch up to the Doctor , he escapes through a gateway by walking backwards into it . Back on the spaceship , two of the crew members staying behind wheel out one of the hibernating Tharil and manage to revive the creature with a large electric shock presumably at the cost of their lives . The creature emerges from underneath its covering and finds the navigation deck with Romana still trapped in the chair . She screams as the Tharil touches her with its hand . Part three . The Tharil , whose name is Lazlo , frees Romana . When Aldo and Royce search for him , he hides , and Romana pretends she is still connected to the machine . The Doctor can see Rorvik and his men on the other side of the mirror . Biroc explains to the Doctor that the mirror is a gateway to E - Space . The Doctor ' s damaged hand is healed by the time winds , and K9 can pass through the mirror and be healed , but for him it wouldn ' t be permanent . Biroc and the Doctor go to a mansion . K9 is getting worse , and when he hears Packard and Lane discussing odd readings , K9 decides to investigate . Packard and Lane have noticed that distances seem to be getting shorter . They go back to the ship , seen by Adric , who follows them and meets up with Romana . Romana and Adric follow Lane to the damaged area of the ship and discover that the ship ' s hull is made of dwarf star alloy . K9 finds Romana and Adric , repeating warnings . Adric tries to shut him up , and Romana is captured by Lane and Packard . In the ship Lazlo rescues Romana and takes her to another timeline . Adric and K9 hide on the MZ laser which the slavers are taking back to the Gateway . In the Gateway , the men see Lazlo and Romana pass through the mirror . Lazlo is healed , and he and Romana go to the mansion . They see the Doctor and Biroc eating at a table with Tharils . Biroc tells the Doctor the Tharils crossed the timelines to build an empire , enslaving humans . When the Tharils turn on the Doctor , Romana runs to him . Gundan robots enter , signalling the start of the human rebellion . The Doctor and Romana suddenly appear in the same hall but at a different time , surrounded by Rorvik and his men . Part four . Rorvik won ' t listen when the Doctor says only time - sensitives can go through the mirrors . K9 arrives and tells the Doctor that the dwarf star alloy in the slavers ' ship is causing the Gateway to contract . Rorvik threatens the Doctor , who is standing near the mirror . Biroc , on the other side , tells him to do nothing . Adric arrives and threatens the slavers with their own MZ laser . The Doctor and his friends escape . The slavers see their ship just outside and realise the Gateway is contracting further . They fire at the mirrors but are unable to break through . Rorvik decides to use a backblast to break the mirrors , but the Doctor realises it would destroy everything . He and Romana head for the ship to short out its power . Meanwhile , Rorvik has his men revive the Tharils , aware that most may not survive , because they will need a navigator . Sagan tries to revive the Tharils , but trying to speed up the process doesn ' t work , electrocuting the Tharils instead . Rorvik finds the Doctor and Romana , but they are rescued by Biroc , who brings them to safety of the TARDIS . The Doctor now understands why Biroc told him to not do anything . Lazlo kills Sagan and revives the rest of the Tharils . Romana informs the Doctor that she is staying in E - Space to help Biroc free his people . K9 , unable to function on this side of the mirror , stays with her . Rorvik starts up his engines , and Biroc takes Romana and K9 through the mirrors while the TARDIS dematerialises . The energy from the backblast destroys the slaver ship , but the Tharils are able to phase to a different timeline and escape the destruction . The TARDIS returns to N - Space . Romana and K9 are ready to start their new lives . Home video and audio releases . DVD releases . " Warriors ' Gate " has been released in a box set alongside " Full Circle " and " State of Decay " , titled " The E - Space Trilogy " . Editing for the DVD release was completed by the Doctor Who Restoration Team . Contents :