The Trickster explains that although Sarah saving her parents was only a small change in the grand scheme of the universe, the village stands on a fault line of the web of time – the remotest of changes, if occurring there, is enough to break open time itself and allow him to walk upon the real world forever, instead of the temporary existence he currently lives in the shadow dimensions. Despite his claims that he cannot be stopped now that Sarah has given him the Earth, Sarah and Luke hurry back through the Fissure.
Meanwhile, elsewhere in the desolate remains of London, Clyde and Rani explore the alternative timeline they have been thrown into – protected from change themselves by the box.
In 1951, Luke insists that Sarah must allow her parents to drive away and face their own deaths in order to restore balance, but Sarah insists – if only to herself – that there must be another way. Above their heads great banks of cloud begin forming – the Trickster is beginning to enter through from the shadow lands.
Soon the fete is called off and everyone hurries to the village hall. Barbara and Eddie are bemused by the sudden change in weather but carry on nonetheless.
Back in the alternate present day, Clyde admits that he feels out of his depth, and Rani agrees. However, determined to find a way home, they chase after the Graske, whom they find stalking the nearby area.
Meanwhile, Sarah explains to Luke that although the Trickster exists fully in the alternate future, in 1951 he is yet to manifest himself in corporeal form, so there is still time to stop him. Sarah laments there may only be one man who can help, but he is never around when she needs him – or is he?
Standing nearby is a large blue Police Box, and immediately Sarah runs up to it, calling out the Doctor’s name. However, the only occupant is a Policeman – the box is not a TARDIS. Sarah, somewhat disheartened, resolves herself and insists she and Luke must deal with the Trickster themselves.
Rani and Clyde discover the remaining humans, all working as slaves to the Graske. Amongst them is Rani’s mother Gita, whom Rani calls out to, unwittingly revealing herself and Clyde to the Graske. However, the creature does not attack them; instead he labels them deviants and ignores them.
Whilst Sarah and Luke hurry to the village hall in 1951, Rani and Clyde approach Gita, who appears not to recognise them. She explains that the remaining humans are used as miners to gut the Earth of minerals, and tells them that the person who handed the world to the Trickster is Sarah Jane Smith. She recalls the legend that by stopping her parents from getting in their car the Trickster was able to enter the world, through something called the Abbot’s Gateway. Clyde realises that they must go to 1951 and warn Sarah and Luke what is about to happen, and the only way back in time is to confront the Graske.
In the village hall in 1951, after Eddie laments that he wished to take his wife and child for a drive that afternoon, Sarah and Luke (still under the alias’ of Victoria and David Beckham) arrive and ask he and Barbara if they have noticed anything sinister in the village recently. They claim they have not, but Barbara agrees to go with them and see if she can find anything that may have changed. Eddie remains sceptical of the two strangers, and stays behind with baby Sarah.
In the alternate future, Clyde and Rani gain audience with the Graske, who explains the minerals his slaves mine will be used to give the Trickster the power to leave Earth and take over other worlds. Clyde realises that the Graske is simply the Trickster’s slave, but the miniature creature denies this fiercely, eventually revealing that his work for the Trickster is payback for the Trickster having saved his life when his spaceship almost crashed. The Graske tries to take the box from Rani and Clyde so that he will be free from the Trickster’s power, but they tell him that he can only have it if he opens the Fissure to let them return to 1951. Ultimately he agrees, and opens the portal for them, but only on the agreement that Clyde stays behind with the box.
Rani hurries through the portal, vowing to save her estranged mother, and upon arriving in 1951, hurries to the village, where Sarah, Luke and Barbara have made their way to the ruins of the Cistercian Abbey. Barbara asks about Sarah’s watch, which she is using to scan for the Trickster, but Sarah insists she cannot say any more about herself, for fear of making the time alteration worse.
Back in the village hall, Rani arrives and asks the crowd if they have seen Sarah Jane Smith. Eddie, very suspicious, indicates his baby girl, but Rani insists the woman she is looking for is older – Eddie realises she wants Victoria Beckham.
As the rain begins outside, Rani hurries to the main square, where Luke greets her and takes her to the Abbey, where again she mistakenly calls Sarah by her real name, thus arousing Barbara’s suspicions. Rani then warns Sarah about what has happened now that she has stopped Eddie and Barbara leaving, and that they must now look to the Abbot’s Gateway, an archway close to where they are standing. Sarah realises this must be the place of the Trickster’s arrival, for hallowed ground is often where the web of time is at its weakest.
However, upon scanning the arch Sarah finds nothing out of the ordinary. Barbara again presses Rani for information about who she thinks Sarah, or rather Victoria, really is. Suddenly the Trickster begins to manifest in the archway, and Barbara is horrified, but before she can see what is really happening Eddie arrives and drags her back to the village hall. Soon both she and Eddie realise that all the odd goings-on are because of them, for everything they touch – such as fruit and flowers – begins to die.
The Trickster grows stronger in the gateway, but Sarah is determined to block the transference with her Sonic Lipstick. However, the Trickster claims that technology is useless in trying to stop him and Luke agrees – there is only one way to stop him manifesting, and Sarah has known this all along. She protests again but Luke insists she must use the Sonic Lipstick to repair Eddie and Barbara’s car and allow them to die.
In the village hall, Barbara recalls what Rani said in the Abbey about their car, and tells Eddie that by not going in it, as he intended, they have done something bad, allowing the creature under the arch to appear. At last she understands that the woman is not really Victoria – she is their Sarah Jane.
In the town square Sarah repairs the car, but confesses she cannot allow her parents to die. However, Eddie and Barbara arrive with baby Sarah in her pram, having worked out for themselves that if they drive away in their car then they will be able to save the day. Adult Sarah protests but Barbara insists, telling them to look after the baby. Luke realises that Eddie and Barbara did not abandon their child, they saved her.
Before they go, Eddie asks his grown-up daughter what kind of life she has led, and Sarah tells him that it is a life of extraordinary things. Tearfully she embraces her mum and dad, and having found peace with them, and herself, she watches them kiss their baby goodbye and get inside their car to drive away to their fates.
Once they are gone the storm raging around them stops, and the half-formed Trickster appears beside Rani, Luke and Sarah, evidently in pain. He claims Sarah has denied him his hunger, but she tells him it was her parents who saved the day – they sacrificed themselves rather than let their daughter convince them. Defeated, the Trickster screeches and turns to dust. Luke then tells his mother that to put time on its correct path they must leave baby Sarah alone.
In the alternate future Clyde and the Graske realise that history is about to revert, and, clutching the box for safety, they wait for time to correct itself. Soon they are back in the abandoned shop where everything began, and true to his word Clyde hands over the metallic box to the Graske, thereby granting him his freedom. As the creature teleports away Clyde turns to the area where the Fissure once opened up.
In the field where the Fissure originally appeared, Sarah, Luke and Rani gather, taking one last look at the village before opening the portal and stepping through to the present, where Clyde is waiting for them. Sarah decides that the Fissure must now be closed forever, and after sealing it she stamps on the Converter so that it will not be used again. That done, she returns home with her friends.
On Bannerman Road Rani is jubilant when her mum and dad arrive to greet her; happy she has them back again. The reunited family go back across the road and Clyde follows suit, wandering home, now in the knowledge that the life he and the others leave can sometimes bring them the best of things, and sometimes the worst.
ome time later, up in the attic, Sarah looks again at the one photograph she has of her parents, and then breaks down in tears. Holding Luke for comfort Sarah recalls how brilliant they were, and Luke confesses he now appreciates how lucky he is to have Sarah as a mother. The two embrace once more, whilst the photograph, now turned over, reveals the legacy of Barbara and Eddie Smith – the last of their messages to each other:
“Mr Smith, I need you”…