The Nightmare Man ( TV story ) The Nightmare Man was the first story in the fourth series of " The Sarah Jane Adventures " , and it was a sort of milestone in the progression of the show . Although occasionally in the past Tommy Knight had reduced his involvement in the programme to concentrate on his school work , by 2009 Knight ' s studies had entered a more demanding phase . " Nightmare " accordingly wrote Luke Smith out as a series regular , but in such a way that occasional returns were narratively plausible . Similarly , Bob Baker had been less willing to allow the expanded use of K9 Mark IV that typified the previous series , due to the 2010 transmission of his Australian " K9 " spin - off . Both Luke and K9 were therefore summarily bundled off to Oxford University at the end of this story , rarely to be heard from again . It was , however , an indulgent farewell for both characters , allowing them both significant parts to play in the action . Tommy Knight ' s departure meant that , from this point on in the series , the only regular left from the first story was Elisabeth Sladen , and if treated as part of the main cast , Alexander Armstrong ' s role as voicing Mr Smith . Synopsis . Luke faces life - changing events , and Bannerman Road will never be the same again . But when Sarah ' s son has his first nightmare , he ' s haunted by a dark figure from his dream s : the Nightmare Man . A strange entity is reaching out to our world through Luke , with terrible consequences for the whole human race . With Luke , Clyde and Rani trapped in a bizarre dreamscape , Sarah must fight alone . As the Nightmare Man grows stronger , only K9 might hold the key . But can Luke summon the courage to face his adult life before the whole world is trapped in an endless nightmare ? Plot . Part 1 . A video recording from Luke begins , with Luke explaining that the world will end because of him , warning that " he " is coming . One year earlier , Luke tells Sarah about Mr . Chandra ' s decision to let him take his A - Levels early , allowing him to start university a year ahead of everyone else . Sarah reminds Luke that they are handcuffed to a bomb , set to detonate in seconds . As a Slitheen tries to make his escape , they are rescued by K9 , who renders the bomb inert . Rani and Clyde arrive and throw a bucket of vinegar over the Slitheen , causing him to explode . When the day of the exam results arrives , Clyde expresses his concerns to Rani and Sarah about Luke . Luke joins then and announces he has four A * ' s and that he is headed for Oxford University . Four days before leaving , Luke sees Rani leaving for school , then joins Sarah in the attic . Luke confides in her about his fear of leaving . Sarah comforts him and offers to make scrambled egg for breakfast , despite a disastrous attempt before . After school , Clyde receives a text messages from Luke , asking to see him , but not to reply . When Rani asks if he will see Luke , Clyde replies that Luke needs to get used to them not being around . Meanwhile , Sarah presents Luke with a leaving gift : her old Volkswagen Beetle , which she had restored . Luke assumes she can ' t wait for him to go , but Sarah admits she is scared of losing him . That night , Luke overhears Sarah and K9 talking about how Luke was a big mistake . However , it turns out to be a bad dream . The next day , Rani visits Luke before school . Luke tells Rani that he had a nightmare , and she urges him to tell Sarah . They conclude that Luke ' s worries about leaving are causing the nightmares . Later , Rani asks Clyde why he hasn ' t contacted Luke . Clyde explains that , despite his concern , he is unsure of what to say . That night , Luke experiences another nightmare ; he finds himself in a dark corridor from school before being approached by a bitter Clyde and Rani . They express their envy about him leaving before them , and mock him for his superior intelligence , calling him an alien . Sarah Jane arrives and takes comfort in Rani and Clyde , and the three brand Luke a loser . Luke then begins to hear the Nightmare Man , who explains that he feeds from his nightmares to gain power . Luke wakes up . He tells Sarah about his nightmares , who then asks Mr Smith to scan Luke . He reveals that Luke is fine , aside from raised anxiety levels . Luke receives a text from Clyde , asking to meet him later . Luke arrives at school , where a surprise party is held by Rani and Clyde . After talking with Clyde , Luke sits down and falls asleep . He meets the Nightmare Man , who prevents him from telling anyone about him . When Luke is woken up by Clyde . Rani recognises that Luke had another dream , but his fear stops him from telling her about it . That night , he tries to send Maria a message , explaining his nightmares , but finds himself unable to . Seconds later , Luke falls asleep . He finds himself in the attic , where Sarah , Clyde and Rani are showing the house to Josh , a replacement for Luke . Mr Smith tells Sarah that Luke is calling from Oxford , but she dismisses it by telling him to take a message . The Nightmare Man then takes Luke outside , where Clyde and Rani are dumping Luke ' s belongings , include a sketch Clyde drew of the two of them together . Just before they set it alight , Sarah quickly arrives to add a photo of them on top . Luke asks the Nightmare Man what he wants , to which he responds that he wants to exist , and that one more nightmare from Luke will grant him access into reality . Luke wakes up . The day before he is due to leave , Rani and Clyde spend the night to see Luke off the next morning . While his friends are asleep , Luke sneaks into the attic with Rani ' s video camera to record a message , the same message that was shown at the beginning . However , just before he can finish , he falls asleep , allowing the Nightmare Man passage into the real world . Meanwhile , Luke finds himself stranded in a black void . Part 2 . Having escaped from Luke ' s dreams , the Nightmare Man heads to Luke ' s room , moments before Sarah enters the attic . The Nightmare Man promptly invades Rani ' s dreams , followed by Clyde ' s . Meanwhile , Sarah is watching the footage on Rani ' s camera when she sees the message recorded by Luke moments ago . A panic - stricken Sarah calls upon Mr Smith and K9 for help . Mr Smith provides Sarah with more information about the Nightmare Man , identifying him as an alien from another universe . With the help of some sentient concrete and an energy boost from Mr Smith , K9 is able to communicate to Luke in his dream . Meanwhile , the Nightmare Man sneaks outside and attempts to ensnare everyone in Bannerman Road . His efforts , however , are thwarted when Luke , Rani and Clyde are reunited in their nightmares . He returns to the attic and disables K9 and Mr Smith before confronting Sarah . The Nightmare Man taunts her by listing off her worst nightmares , but Sarah calls his bluff by telling him to send her to sleep , saying that without the gang she has no reason left to live . Knowing that Luke , Clyde and Rani together are weakening him , the Nightmare Man disappears into their dreams . Rani ' s nightmare begins with her lying on her sofa while a BBC news report is being broadcast . As Rani attempts to switch it off , the reporter , Louise Marlowe , berates Rani for being ignorant . Shocked that she is being spoken to directly , Rani approaches the television screen , where Louise grabs her and pulls her into the studio . Rani discovers her clothes have changed ; Louise questions Rani ' s journalism aspirations and forces her to present a story exposing Sarah ' s adventures . When Rani refuses , Louise asks how often she is put in near - death situations . When the broadcast goes live , Rani is hesitant to proceed when she hears Luke calling out to her . She is reunited with him after imagining a doorway , despite Louise questioning his importance to her . Clyde finds himself working in an abandoned burger bar café . He is visited by an elderly , wheelchair - bound Sarah , who begins to criticise Clyde ' s future and calls him " stupid " . She continues to compare him to Luke , who she claims is working in government and is set to be an astronaut . She tells Clyde that she once went to space , but when Clyde reminds her that he already knows , Sarah reveals that social services are trying to put her in a care home . Clyde tries to leave but finds the entrance locked . Moments later , Clyde hears Luke calling out to him and reunites with him after imagining a doorway . Luke is back in the school corridor , hounded by the laughter of the Nightmare Man . Luke calls out to him , successfully making contact , but is unable to wake up . As Luke is about to give up , K9 appears and tells him that Rani and Clyde are also under the Nightmare Man ' s influence . Luke calls out and encourages them to imagine a doorway into his corridor , soon reuniting with them and weakening the Nightmare Man . When he arrives and sends Rani and Clyde to their own dreams , Luke tells him that their friendship will overcome any hardship . The strength of their friendship overpowers and sends the Nightmare Man into his own nightmare where an elderly Sarah constantly tells him about Luke ' s success . The three then wake up and are reunited with Sarah . The next morning , Sarah tells K9 to accompany Luke to Oxford , allowing him time to make peace with Mr Smith . Luke says goodbye to the gang and leaves Bannerman Road in his new car . Story notes . Ratings . " to be added " Filming locations . " to be added " Home video releases . Blu - ray releases . In both releases , the first episode is re - edited to include a dedication at the beginning to the memory of Elisabeth Sladen . This obviously was not part of the original broadcast , which occurred a number of months before she died .