The elderly Rani listens as the boy, Adam, explains that he lives across the road and after having heard the stories about her at school, could not resist the urge to investigate. He watches as she takes a box from the windowsill and sorts through its contents - photographs of the people she used to know and love - her parents, Sarah Jane Smith, Luke, and Clyde - now all gone.

She remembers Sarah and how she changed her life, something she never thanked her for because she never thought that one day the adventures all four of them shared together might end. She recalls the monsters she witnessed back before aliens were commonplace visitors to Earth - when not everybody knew everything.

Adams asks how she came to be alone in the attic and she claims it was simply because of a single mistake she made when she was a teenager.

Back in 2009 the teenage Rani, having found a report of strange lights in the sky on the Internet, hurries over the road to see Sarah, Luke and Clyde and tell them about her discovery. Unfortunately, they have already uncovered this and managed to confirm with Mr. Smith the computer that it was simply a bolt of lightening. Rani then listens as her three friends recount the latest adventures of their old companion Maria, who is now living in America and assisting the government with alien cover-ups.

Feeling dejected Rani returns home where she finds an e-mail on her computer from an old friend of her own - Sam Lloyd, whom she lived near before moving to London but lost contact with when he stopped returning her calls. Now having found something he would like her to investigate, he has broken his silence.

She returns to her old hometown to find Sam - more irritable than she remembers - who takes her to the now-abandoned amusement park. He claims that recently, four people have disappeared after entering the grounds, all homeless and therefore passed over by the police. Soon after a young boy went snooping around one of the old rides and claims to have seen a demon haunting the attraction. Having heard from Rani that she now spends her life hunting aliens, Sam asks her to investigate.

Rani is keen on the idea but finds herself going on alone - despite wanting someone to solve the problem, Sam has no interest in doing so himself. He wanders off as Rani makes her way inside the park, making a log of her findings on a voice recorder. Soon she is discovered by the park's caretaker, Harry Sowersby, who tells her to leave.

She bluffs her way into his office by claiming to have twisted her ankle, and once they are inside she begins to question him about there being someone or something living in the park. He rebuts the idea but when a ghostly voice is heard announcing "playtime is beginning", Rani's suspicions are confirmed and she leaves to find the source of the noise. Left alone, Harry turns to his wash basing mirror, where a haunting red face appears and recites the incantation once again.

Rani ventures outside and sees four people - human but with red eyes - marching across the park and onto various rides. The attractions begin working again and the possessed punters dutifully enjoy their outing.

Back on Bannerman Road, Sarah realises that Rani has gone missing and is worried she may be responsible after dismissing her friend's story earlier that day. Realising they need to find her, Clyde prepares to search Rani's house, under the pretence of having left a book there.

At the amusement park, Rani refuses to answer calls from her friends whilst the spectacle continues. The demon's voice announces that "playtime is over" and the attractions all come to a halt.

Having searches Rani's room, Clyde returns to the attic and shows Sarah and Luke the e-mail Rani received from Sam. Sarah is hurt that Rani has revealed all of their secrets to the boy and calls on Mr. Smith to investigate Sam Lloyd, whom they discover is actually living in a care home after his parents died in a car crash.

Meanwhile, Rani records her findings just as Harry arrives, telling her again that she should leave. Refusing, Rani heads towards the ride the four abductees came from before mounting the rides. She heads inside with Harry following close behind, just as playtime begins again.

Elsewhere, Sarah, Luke and Clyde arrive at Sam's care home - and he seems to have been expecting them. Shrugging off their pleasantries he tells them he will reveal Rani's whereabouts:

"She's with her."

Rani eventually finds her way to a hidden room at the heart of the abandoned ride, there she finds a girl standing with her back to her. This, Harry claims, is his own little girl, Eve, and she needs somebody to play with. He swiftly locks the door leaving Rani and Eve together. Rani panics but then turns to face her new companion - the red-skinned demon.

Having learned little from Sam other than the mystery of the amusement park, Luke elects to stay behind and talk to him whilst Sarah and Clyde go in search of Rani. Sam watches them go.

Rani tries to speak with Eve, who communicates telepathically. Reading the young human's mind, Eve reassures Rani that she need not worry so much about proving herself to her parents and her friends - she knows they love her, and that they are proud of her. Rani is astonished.

On their way to the park, Sarah and Clyde bicker about their friendship and who discovered who - Sarah insists she chose her allies but Clyde claims she had no choice. He teases that her memory may be failing with age, and runs ahead leaving Sarah to smile.

Rani asks Eve about her own childhood and reluctantly she reveals that she is an orphan. Many years ago a war between two alien races, neither of them her own, raged across time and space, and due to her people being able to read time lines, they came under attack and were exterminated. Her parents managed to save her by placing her in a ship and sending her off into space. It is so long ago now, that she can no longer recall her own mother's face.

As Sarah and Clyde arrive outside, Rani watches the homeless people forced to play on the rides. She asks why they do so and Eve claims that she makes them - she saw that they were sad and alone and so made them be happy again.

Outside Clyde tries to talk with one of the players, but he receives no reply. Soon Harry arrives.

Back at the care home Luke talks to Sam about losing the people they love. Sam claims that Luke is lucky to still have a mother, despite losing Maria; he has no other friends or any family to care for him. However, as he turns to his mirror he insists that he is not alone; and immediately the red face that spoke to Harry appears before him in the reflection.

Whilst Sarah and Clyde try to find out from Harry where their friend is gone - the old man insisting she is still safe - Rani urges Eve to let her human playthings go. Eve ignores this and instead returns to reading Rani's mind, seeing the events of the morning in the attic and telling her that despite how she felt, she needs Sarah, Luke and Clyde. Reacting badly to the intrusion, and once again rejecting a mobile call from her friends, she offhandedly claims:

"I wish they'd just leave me alone"

In the office Harry leads Sarah to his mirror, seemingly at the command of the face in the reflection. Likewise, Sam grabs Luke and presents him to his own mirror; the face inside wants to know more abut the extraordinary mother and son.

At the abandoned ride Eve presents Rani to yet another looking glass, and offers t show her the future. Rani protests, claiming it is wrong to know. Eve goads her, claiming that is a doctrine imposed by Sarah Jane. Convinced, Rani agrees to look into the glass, but when she does the future she sees is not a happy one.

Up in the attic, in 2059, Adam lights some candles as the elderly Rani prepares to tell more of her story.

She recalls how the red face in the mirror - knows as 'Ship' - showed Luke his past, how he was created in a laboratory, and then his future as a successful university graduate. She then turns to Sarah and shows her her entire life; from losing her parents to growing up on her own and then to her travels across the stars with a man known as the Doctor - who cared for her despite his changing face and who she found again so many years after they parted.and now, Ship claims, he is coming back. Sarah reels away from the mirror and is quickly dragged out of Harry's office by a concerned Clyde.

Rani bursts into tears having seen her own lonely future, and swears that she will not allow it to happen (but as the Elderly Rani knows, it already has). She turns to Eve and tells her that she will be allowed to return to the stars, promising to find her lost space ship.

At the care home Sam is astonished by what the mirror has revealed about Luke's past. As the two boys talk, Sam reveals how lonely he felt when Rani started her new life in London, but Luke assures him that she did not forget about him, as if she had she would not have revealed so much about her secret adventures with Sarah. Luke then begins to realise that Sam lured Rani back home to make her face the alien in the park - Sam was the boy who went inside and saw a demon. Sam reveals he knows the creature not as a demon but as Eve, and tells him that she is his friend. He explains that when he found her she read his mind and found out about Rani and Sarah. She then told Sam to bring her to her so that she could help her get away from Earth.

In the park Sarah contemplates the future she has seen - the image of the TARDIS stood in her attic. Clyde forces her to consider the present by reminding her Rani may be in danger, and they hurry away into the ride Rani ventured into earlier. After a few moments they run into Rani and Eve, and Sarah chides Rani for underestimating the danger Eve may pose. Angrily Rani leads Eve away but Sarah and Clyde are close behind.

Meanwhile, having left to find a drink, Luke returns to Sam's room at the care home to find that he has disappeared, leaving behind a note that reads: "It's not Eve who wanted Rani". He calls Sarah to explain all that he has seen and she tells him to check Sam's computer for any clues as to what is really going on.

Sarah then hurries outside to find Rani showing Eve the open air. Succumbing to a childish fit of glee Eve uses her powers to activate all of the rides again. Harry arrives and warns her it is not safe to be outside, but she does not listen and instead manipulates the rides, making them move faster and faster.

Returning to Harry's office, Sarah summons the face in the mirror. Immediately she senses that Eve has been allowed outside, and orders that playtime must stop. She tells Sarah to bring Eve back to her, for she is too young to be able to control her powers. She explains that she is Ship, the computer of the craft that brought Eve to Earth. She is currently rebooting after the crash and has found Harry to keep her ward safe by distracting her with the rides and attractions.

Meanwhile, Rani grows tired of Eve's manipulation and makes to leave, but her new alien friend has other ideas. Taking possession of Rani she forces her to stay, just as Sam arrives as the fairground. He watches as Eve's powers start to backfire, recoiling on her and burning her mind. Sarah arrives and makes her stop taking control of the rides, warning her that if she truly wants friends she must accept those who choose her, not those she forces to play. Harry also urges her to release her prisoners but she confesses that she does not know how, only Ship can help.

Sarah, Sam and Clyde take Eve to the beach, where Harry found her after the crash. They locate her vessel, buried in the sand, and go inside. Once there Ship is able to manipulate Eve's mind and release all those she has possessed, including Rani, who then hurries away from the park with Harry to join the others by the sea.

Sarah speaks with the ship and warns her that Eve will not be safe of Earth - not everyone is as understanding as Harry and Sam. Ship then reveals that it was she who made Sam summon Rani, for she knew it would lead to Sarah following, and it is Sarah she requires - for only she has access to the power Ship needs to fully recalibrate - Sarah is the only human with a black hole in her cupboard.

Sarah calls Mr. Smith and asks to be put through to K-9, her robot dog currently drifting in space around a black hole, keeping it in check so that it cannot expand and envelop the Earth. He makes contact and sends his coordinates to Ship so that she can lock onto the black hole and drain it for fuel. His job done, K-9 teleports back to the attic for good and is given a frosty reception by a somewhat covetous Mr. Smith.

Harry and Rani arrive in time to see the ship powered up and ready to take Eve back into the stars. Sam apologises to Rani for being jealous and Eve offers the orphan the chance to travel the universe with her. He accepts and the same chance is given to Harry, who also agrees.

Sarah, Rani and Clyde prepare to leave the three new crewmates for take-off, happy that they will make a good team. However, Ship has one more task to complete. She thanks Rani for helping to keep Eve safe and offers to grant her the wish she made back at the amusement park - that Sarah, Luke and Clyde would leave her alone. Rani realises the folly of what she said, apologising to Sarah and claiming she was in a bad mood. However, Ship has taken her at her word and promptly makes all three of her closest friends disappear forever.

Back in 2059 Rani tells Adam the rest of the story; she left the ship and watched it take-off, leaving Earth behind and her alone in the world apart from her parents. As time moved the prophecy of the mirror came true - she became the mad old woman of Bannerman Road.

Adam then takes his turn to speak, claiming that he does not really live across the road. For a second his eyes glow red and Rani realises that he is an alien - Eve and Sam's son. He claims that he has been send by his mother to fix the mistake and bids her one final wish. She asks that Sarah, Luke and Clyde should never have been taken, and this he grants. As the timelines change the attic fills with life and both Rani and Adam disappear.

Fifty years earlier, Sarah, Clyde and Rani leave Eve's ship together and run for cover as the craft rises out of the sand and ascends into the skies. Rani apologises to Sarah for causing such trouble by going to the park alone but thanks her for the extraordinary life she allows her to share. Sarah also apologises, and tells Rani that by trusting Sam with their secret she has proved that not everyone is out to harm them.

Soon they all return to Bannerman Road to welcome K-9 home, and after Rani and Sarah vow to face the future together - Sarah still recalling the ghostly prophecy about the TARDIS - they join the boys for a photograph.