Cat and Mouse ( comic story ) Cat and Mouse was the seventh issue of " Prisoners of Time " featured the Seventh Doctor and his companion Ace . Publisher ' s summary . Our yearlong celebration of " Doctor Who " s 50th anniversary continues ! The Seventh Doctor takes the spotlight in this issue of a 12 - part epic adventure featuring all 11 incarnations of the Doctor ! In a 19th - century Scottish castle , a live - in nurse ' s concerns about the elderly couple in her care are allayed by a visiting doctor and his curiously modern female companion . Plot . Scotland , 1830 . Maid Mackenzie serves two elderly patients in bed , and is hoping the two patrons will get better . She has just sent for the doctor to figure out why they are both so sick . She looks up and spots that the Seventh Doctor and Ace ( Ace is wearing 18th century attire , with her jacket ) have entered the room . The Doctor comments that Ace gets the chills quite easily and that she loves her jacket , and won ' t leave it behind . The Doctor examines the patients ( including listening to their feet and smelling their arm - pits ) trying to find out what is wrong with them . The master of the house , , arrives , and states that the Doctor is not the doctor he sent for . This raises Mackenzie ' s awareness , saying that she thought that the Doctor was their family physician , which the Doctor states that he never said he was . Campbell states that it doesn ' t bother him , and that the Doctor was recommended by their own physician , Dr Lewis . The Doctor then asks Campbell to fill him in on the patients background . Campbell said they ' re his Great Aunt and Uncle , Ruth and Gibson Campbell , and that they fell ill about 3 months before the Doctor ' s arrival . The Doctor also enquires that the grounds and estate belongs to them . Campbell states that the grounds are part of the Campbell ancestry , the Doctor also enquires if it belongs to either himself of the two patients in bed . Campbell starts to get annoyed , saying that the estate is theirs , and if anything should happen to them , he ' d get their estate . The Doctor doesn ' t cause to defend , saying that he is " The Master of the house " , which Campbell agrees with a smile . The Doctor and Ace leave , apparently to read a few texts he brought with him in his carriage , and with Campbell ' s permission , heads off . Ace starts to enquire as to why the Doctor was asking so many questions . The Doctor states , that he needed to " cut straight to the bone " , and shed some light on the situation . He also learned the fact that Campbell isn ' t the person he says he is . He also states that the ' aunt ' and ' uncle ' are not human . They head to the TARDIS to examine a spoon that the Doctor has stolen from the bedroom to find out exactly who they are . The Doctor sends Ace for a walk around the castle with a device that picks up on the same energy that dragged the TARDIS off course . Ace walks into the kitchen , and the detector goes off . Pointing at a small door at the back of the room , Ace decides to investigate , despite the Doctor saying not to take any risks . What she finds leaves her flabberghasted . Meanwhile , the Doctor is confronted by Miss Mackenzie , who states that the Doctor had no right to talk to Campbell the way he did . The Doctor reminds her that something is not right , and then enquires as to how long she ' s been working there . She says two months , and that nothing has changed in their condition since she arrived . It ' s also the reason why she didn ' t question him when he arrived , all she wants to do is help . Mackenzie is suddenly overcome with fear , saying something is not right about Mr Campbell . Ace runs out of the house , saying she has found what the Doctor was looking for . He then asks Ace to lead the way . Ace and the Doctor walk down the back steps find a fully decked out computer room . They then figure out that the door was left unlocked , meaning that they were meant to find it , and could possibly be a trap . The Doctor then states that only the Master could come up with something like this . They both investigate the equipment , only for a massive one - eyed creature with razor sharp teeth appear before them , but it ' s chained up . The chain snaps , and The Doctor orders Ace to run . They manage to beat the Beast up the stairs and lock the Doctor . But the creatures strength breaks the door with ease . Ace then throws a can of Nitro - 9 at the beast , and it explodes , killing the creature . And the patients stir in front of Mackenzie . The Doctor examines the body of the creature , determining that it ' s a Gulwort , stating that its a creature that drain the life force of its victims , and would have certainly have killed both the Doctor and Ace easily . Mackenzie runs down to the Doctor to tell him that the Campbell patients have stirred , but haven ' t awoken . The Doctor , Ace , and Mackenzie run back into the building and up the stairs . only to have Mr Campbell block their path . He then shifts into the Master . The Doctor just degrades him by calling him cheap . He then also states that he knew all along . then reveals that he ' s been working with a new partner , or " companion " of the Doctor ' s , to which the Doctor doesn ' t have a clue what he is talking about . The Master then states that he hasn ' t met him . . . yet ! And that he ' s been siphoning the life force from the " Campbells " to transmit power to his partner , helping him conduct a revenge scheme against the Doctor . The Master gloats , saying that he loves causing the Doctor pain . The Doctor then tells the Master that both himself and Ace have killed his main supplier ( the Gulwort ) . But before the Master can retaliate , the Doctor pulls out the device that has been keeping the Campbells asleep . and subsequently deactivates it . The " Campbells " revert back to their true form , Aerolith s , whilst the Master curses vengeance . The Aeroliths recognise the Master as the one who trapped them and chase after him . Mackenzie cannot take it in , that everything she ' s been told was a lie . The Doctor explains that the Master would never lower himself to be a nursemaid , and that the creatures will catch him eventually , and that he has made new enemies for himself . He also states that this will only fuel the Master ' s vengeance against him , and that he ' ll now be deadlier than ever . As the Doctor and Ace bid farewell to Miss Mackenzie , the Cloaked Figure arrives , and snatches Ace . . . Notes . " to be added "