Confabula ( short story ) Confabula was the sixth short story in the Short Trips anthology " " . It was written by Ian Potter . It featured the Fifth Doctor and Nyssa . Summary . The Doctor and Nyssa have landed on a devastated planet . They find themselves on a train in the midst of where a murder has taken place . The Doctor says they should separate , and he ends up in business class . He reads a magazine , carefully ignoring the two people in the compartment with him . Nyssa , meanwhile , has made her way through several cars , and ends up in a garden car . She is accosted by three teenagers , Guillame , Burdine and Jennette , who threaten her with their tools until she explains that she ' s from off - world . They think she is here to help with their rebellion and take her to their sleeping compartment . Back in business class , the Doctor is unable to deflect the attention of his compartment mates , Emiliege and Mellin Kinloch - Jones . She wants him to play Perfidy , but he manages to deflect the conversation and give them the impression that he is an inspector investigating recent suicide s . They explain the train system to him . The planet was devastated long ago , and the trains are constantly running . The people on the train - cities never disembark ; they are hoping things will get better . Nyssa ' s new friends introduce her to their father , Mr Villeharduin . They explain to Nyssa the class system of the train and their need to reform the system . As the train enters a tunnel , the Doctor sees a reflection of his face in the window — only it is not his current face , but rather his first incarnation ' s face . A Tunnel Wraith appears at the window and begins to break in . Emiliege and Mellin try to get the Doctor out of the compartment , but he is starting to realise that things are not what they seem . The Doctor suddenly finds himself in a well - furnished room . A disembodied female voice speaks to him . The voice becomes a beautiful woman who introduces herself as Maya , a Psionosphere , or planetary computer . She created the illusion of the world with the train as an adventure for the Doctor and Nyssa . She wants them to stay with her forever . The Doctor is angry that she is deceiving Nyssa , but Maya , able to read the Doctor ' s surface thoughts , says that she is only doing the same thing he does for his companion s . The Doctor is unable to convince Maya that he doesn ' t want to stay . She finally threatens harm to Nyssa if the Doctor doesn ' t stay . She kisses the Doctor , and he promises to stay if Maya lets Nyssa go free . The Doctor steps back into the illusion , congratulating Nyssa on helping with the bloodless rebellion . Nyssa sadly informs him that Burdine died in the rebellion . The Doctor tells her that he will be staying behind , and that she must be " the Doctor " now . He gives her the codes to remove his telepathic link from the TARDIS . Nyssa , crying , enters the TARDIS and enters the code . She feels a flash of pain , and the Doctor is there in the TARDIS with her . He explains to her what really happened , and tells her that the codes her gave her actually strengthened his link with the TARDIS , allowing him to break free of Maya ' s influence . The Doctor tells Nyssa that he left Maya with the illusion that he has stayed with her . Nyssa wonders if their leaving Maya is the illusion . Meanwhile , Maya watches happily as the Doctor takes part in the illusion she gave him of escaping her . She occasionally wonders if his staying here is an illusion he gave her . Continuity . " to be added "