In her attic, Sarah adjusts a telescope so that she and Luke can view a formation of lights in the sky unseen for four thousand years. Maria enters and tells her about her father’s intentions to move home. Sarah comforts her, reasoning that he cannot be blamed for wanting to keep her safe. Soon Alan joins them and tries to convince his daughter they must go, but she manages to change his mind, and he finally accepts he must adjust to the revelations put before him. Soon the light shw begins and Sarah looks out in awe
“The universe is smiling on us Alan”
“Let’s hope it always does”
The next day Luke sits in his living room reading a book with the television playing in the background. On the screen is a news report showing two parents pleading for information concerning their lost son Ashley, whom they believe has been abducted. After a while Sarah enters the room and watches the report, whilst over the road Maria and her father do the same.
A picture of Ashley is shown and much to everyone’s shock, he is revealed to be the spitting image of Luke. Sarah rushes to the attic and calls Mr Smith, who has been monitoring the news. He claims that to determine whether or not Luke really is Ashley he must scan him, but Luke protests that he created by the Bane, he has no memory of life before he awoke in the Bubble Shock factory.
Sarah insists Mr Smith examine him and the result of the test confirms that Luke is indeed the missing boy. Sarah claims it must be a mistake, saying he cannot be human, as he has no navel. Mr Smith tells her it may have been removed by the Bane when they captured him because to them it served no purpose. As Luke embraces his mother, Sarah asks her computer if there is any chance the scan may be wrong, but he insists the likelihood of failure is around four billion-to-one.
Some time later Alan and Maria sit around their dining room table. Chrissie enters boasting the fact she always had suspicions that Sarah Jane was not all she seemed, and tells them that she has called the police. Maria is distraught and runs outside, where she is joined by Clyde, who has heard the news as well. The Police soon arrive and Sarah calmly opens the door, asking them to wait for her to say goodbye to Luke. She returns inside and tries to calm the young boy, who is frustrated he has no memories of his would-be parents.
She tells him he must go, to be with the people he belongs with. She leads him outside where Ashley’s parents arrive and embrace their lost boy, who still has no recollection of them. Sarah tries to explain she had no idea of the child’s past life and is taken away in a police car. Luke and his parents leave soon after.
At the police station Sarah is informed by the Chief Inspector that UNIT have managed to secure her freedom and she is permitted to leave, whilst elsewhere in the city Luke arrives at his old home. He is bemused by the revelations his parents present him with concerning his life before he knew Sarah, finding his hobbies and tastes have since changed dramatically. He retires to his room but the door is locked behind him, leaving him trapped. Downstairs his parents sit watching the television. They switch over the channel and are bathed in a green light. They lean toward the screen and laugh:
“Xyloc are you there? We’ve got the boy”
Back on Bannerman Road Maria arrives at Sarah’s home. She approaches her friend, who stands in the living room and they embrace, but after a second Sarah pushes her away. She explains that Mr Smith has confirmed Luke is indeed the child of the two parents from the news report and then claims that it is not the only mistake she has made; children must play no more part in her life. She reminds Maria that her life is dangerous and for her own safety she must forget her, as should Alan and Clyde.
She shows Maria to the door and the young girl leaves. Sarah then returns to the attic, somewhat crushed by the ordeal of loosing both a son and a close friend in the same day. She reclines on a chair but is interrupted by Mr Smith, who emerges from his hiding place in the chimney without summons. He tells her that she, like all things in the universe needs a purpose, and explains to her that he has discovered the Pharos Institution, a research facility, have discovered a way of manipulating kinetic energy using alien technology. Sarah decides she should investigate the company, now without any children to look after, and prepares to leave.
Back in his room, Luke is unnerved when his father arrives. He asks why he was locked in his bedroom and he claims it was to stop him running away again. He then tells his son that he will not be allowed to go to school, even to see his friend Maria and Clyde. Luke asks how he knew their names despite him never having mentioned them, but his father simply leaves and locks the door, claiming he will never see them again.
Clyde and Maria meanwhile return to their lives at school, upset by recent events but understanding Sarah’s pain at loosing a son. Clyde decides that they should visit Luke and opts to skip school in order to see him, and his friend follows. They make their way to the courtyard before Maria is caught and sent back to lessons, but Clyde succeeds in jumping the fence and running off.
Sarah arrives at the Pharos Institution, a grand building inhabited by a group of scientists. She is shown around by Professor XXX, who encourages the publicity Sarah can give the organisation and thus guides her around some of their laboratories. In one they witness an experiment involving a headset that takes the latent psychic abilities of all human beings and utilises it so as to move objects, in this case a basketball.
After witnessing the ball burst the Professor explains they are having trouble with MITRE, the name for their energy focus stabilisation. She then takes them to see Nathan Goss, a child genius who has been working on MITRE. Sarah finds the young boy remarkably rude to his adult company, and before she leaves she turns on him
“I used to know someone your age who could wipe the floor with your intelligence Nathan, and wipe the floor with you to.”
She turns and leaves with the Professor, but Nathan has the last word
“We’ll see about that”
Clyde eventually arrives at Luke’s new home, but is turned away by his mother. She dismisses his claims that Luke is not theirs and presents him with a photograph taken at Ashley’s birthday party. Unsatisfied but defeated Clyde leaves, unaware that upstairs Luke is pounding on the window of his bedroom trying to get his attention. Failing to do this he begins rummaging around his bedroom, looking for a ruler.
Clyde reaches the local park and calls Maria, explaining to her his disbelief at the situation concerning Luke. He claims the photo given to him may be faked, and decides to take it to Sarah Jane.
Luke uses the ruler to break the lock on his door and sneaks downstairs. In the living room his parents sit giggling, when suddenly Nathan Goss enters:
“We’ve got a problem”
Sarah returns to her attic where Mr Smith explains the profile of Nathan Goss, who has been called the “Young Einstein” by some critics. She fobs the boy off as an “obnoxious brat”, and claims there is something about him that made her blood run cold. The computer goes on to explain that MITRE is beyond even Nathan’s intelligence and that the Pharos headsets could, in the wrong hands, destroy planets. He tells her that to find out more about the technology he will need one of the headsets, and Sarah agrees to go and steal one.
Nathan explains to the two adults before him that Sarah Jane has seen the Telekinetic Energiser, and fears she may know too much. They protest at his bluntness but he insists the mission they are working toward is his, and Sarah must not be allowed to interfere. Luke’s mother claims an entity known as the Xyloc told them Sarah might interfere and not to worry, but Nathan is dismissive of the Xyloc’s trustworthiness. Suddenly they hear Luke coming down the stairs and chase him outside, managing to drag him back into the house before he can escape.
They escort him back to the living room where his would-be parents disclose their true identities. Reaching up to their foreheads they unzip their skin to reveal they are in fact Slitheen, now housed in slim-line skin-suits. Luke then turns to Nathan, who eventually reveals he too is one of the creatures, the same infant he encountered when they tried to destroy the Earth only to be stopped by Luke, Sarah, Maria and Clyde.
Clyde arrives on Bannerman road only to find Sarah departing in her car. He finds the spare key to her door and ascends to the attic, where he manages to summon Mr Smith. He shows the computer the photograph of Luke and it confirms it is not real.
“It is fake. I faked it”
Clyde seems stunned by this revelation, and Mr Smith tells him:
“I am a Xyloc. I have a purpose. And you Clyde, are a part of it”
Suddenly two beams of light blast from the console and engulf Clyde, causing him to disappear. Mr Smith is left alone in the attic, laughing.