Several months later, the Doctor, in top hat and evening dress, and Amy, also dressed for the period, pay a visit to the opera house to watch a performance of Orphée. They are astonished by the amazing performance by Cosette but the Doctor recognises by her reduced blink rate that she is in a hypnotic trance. He takes Amy to the stage door but Valdemar rushes Cosette through the waiting fans and into a carriage. A young man calls after Cosette but to no avail.

The Doctor guesses that the young man is Cosette's boyfriend and Amy invites him to a café. There, the young man explains that he and Cosette were engaged until she went to Valdemar. He hadn't expected much to come of Cosette's ambitions because she was such a poor singer. However, she spent more and more time with Valdemar until one night she never came home.

His story is interrupted by a scream from outside. Everyone rushes to the alley across from the café where a man lies dead. The Doctor sees blood around the man's ears. He surmises that the poor man only had a couple of days to live anyway. Amy wonders why anyone would bother to murder him. She also says that the scream they heard was a young woman's.

The Doctor takes the young man and Amy to Valdemar's house where they gain entry via a skylight in the roof. In one of the rooms they discover a series of chambers wreathed in a green gas. Each contains a young woman, the girls from the opera, wearing gas masks. The Doctor looks at the machinery in the room and recognises a DNA sampler. Just then, Valdemar enters and removes the masks from the girls. The three intruders hide in the shadows. He gives each a target and tells them to collect genetic samples. He then says that when he has selected his victims the girls shall sing them to their deaths. The girls then levitate and fly out from his house. One of them knocks on a bedroom window across the town and when the owner opens the curtains she crashes through the window, exhaling green gas.

Meanwhile, Valdemar tells the three intruders to come out from their hiding places. The Doctor asks how the girls managed to levitate but Valdemar insists that it is beyond the Doctor's comprehension. He releases Cosette from her chamber and tells her to sing to them all. Cosette emits an ear-shattering scream.

Salzburg 2098. Eldritch Valdemar is found guilty, as leader of the Eugenic Cult, of murder, treason, mental domination and genetic manipulation. He points at four men in the courtroom, accusing them of treachery. The robotic judge says that the four have bought their freedom with their testimony and Valdemar is sentenced to death. Before the sentence is carried out he swears to have his revenge and then Valdemar is hit with a blast of energy.

Back in Paris, 240 years earlier, the Doctor is chained to a wall with Amy and Louis (Cosette's boyfriend). Valdemar instructs Cosette to take a sample from each, which she does by kissing them deeply. Louis can see the paper bearing the names of all Valdemar's victims: the same four surnames repeated over and over again. The Doctor guesses that the targets are actually the victims' descendants who he wants to prevent existing. He has to make sure that none of the victims of his plan are his own ancestors too, hence the DNA samples.

Valdemar speculates that the Doctor, like him, is also from the future. He says that he got there when his death by molecular dispersion resulted in him being miraculously transported through time. The Doctor sees that someone is behind all this but it isn't clear who.

Valdemar goes off to check the samples and Amy uses a bent hairpin to free herself from her manacles. She releases the other two and they make their way to Valdemar just as he discovers that neither the Doctor nor Amy is his ancestor. He orders Cosette to kill them. Louis surmises that, as he is being spared, he must be Valdemar's grandfather. He snatches a flask and threatens to drink it, poisoning himself, unless Cosette is returned to him. Valdemar refuses and is swept into the air by his 'daughters of the night' to commit the slaughter. Louis manages to grab Cosette and drag her to the ground. The Doctor asks the girl to take him in pursuit of Valdemar.

They fly through the night. Valdemar leads them to the roof of Notre Dame Cathedral for a showdown. The Doctor uses his sonic screwdriver to ring the cathedral bells which looses the hold he has over the girls. They turn on him and he plunges from the roof.

In the morning, Amy Pond (in nurse's outfit) brings him a cup of tea. She comments on how loud the children are as they play in the garden but Arthur says he likes to hear the laughter. He adds that he never had any children of his own and when his wife died in 1988 he had no relatives left. Sister Frost arrives and orders Amy to stop chatting and get on with her other duties. She tells Amy that another resident has died in the night but when Amy enters the room the body has already gone. This strikes Amy as surprisingly quick. Amy picks up a photograph of the dead woman, Margaret, as a child. When she turns around the young Margaret is behind her.

The Doctor, meanwhile, is talking to Miss Bruce who is in charge of the nursing home. He asks her about bodies disappearing in the middle of the night but then interrupts her reply to tell her that she is about to say she doesn't know what he is talking about. He says that she has been arranging for the undertakers to bury empty coffins and that he knows that this is true because he was there when they were dug up by archaeologists eight hundred years in the future. He also accuses her of only admitting people with no friends or relatives. He suggests that she isn't behind the disappearances and then asks her how long the home has been allowing children to play in the gardens. Miss Bruce calls him insane, saying that there are no children even though a group can clearly be seen through the window behind her.

Amy tries to engage the young Margaret in conversation but Sister Frost drags her away to the laundry closet at the other end of the building despite the fact that they are standing beside a room clearly marked 'Laundry Closet'.

That evening, as the sun sets, the Doctor takes Arthur out to the TARDIS. Arthur tells him that his friend, Bert, saw the boy with no face the night before he died. He expects to die soon. The Doctor changes the subject to the children. Arthur says that they have only appeared recently and don't like to get too close to the building. They also notice that the children's clothes and games seem rather old-fashioned. When the Doctor approaches them the children says they cannot tell anyone where they came from or the grownups will put a stop to their games. Margaret tells Arthur not to worry because he will be joining them soon.

Amy rushes up to tell the Doctor that there is a girl running around the home but the staff can't see her. He replies that a perception filter is at work and is probably shielding an alien hiding place. Amy remembers the laundry closet that was invisible to Sister Frost. They head straight there.

Arthur seems to be suffering chest pains but insists that he hasn't had so much fun in years. The Doctor says the perception filter is set to local fauna so he and Amy aren't affected. The laundry closet is revealed as a huge, high-tech alien nest. Nurst frost is within, as are a number of blank children. Frost's head opens up to reveal an insectoid robot which accuses them of being a threat to the surrogates. As weapons open fire Arthur dies of a heart attack but a boy with no face steps forward and surrounds the body with energy. The corpse vanishes and the boy grows a face. He turns to the robot and demands it to stop, adding that the Doctor and Amy are his friends. The robot immediately designates them as non-hostile and ceases fire. Amy turns to the new Arthur who is confused as to why he is suddenly so short.

The Doctor demands an explanation from the robot. It says it is a Vorlax regeneration drone that provides replacement bodies for dead infantry and places their consciousness within at the moment of death. It was hit by enemy fire, causing a teleport malfunction, and arrived on Earth where it activated its camouflage. The Doctor repairs the teleport device and sets it on a countdown for departure to an uninhabited garden world. Amy says that it was actually doing a good thing, giving people a second chance for life. She asks what will happen to the kids and if the other residents don't deserve the same chance. They take the children to the residents' sitting room and ask them if they would like to be made young on a planet millions of miles away. He tells them they have to make up their minds immediately.

The next days' news reports that all of the residents of Hawkshaw nursing home have disappeared simultaneously but the reason is that they have all emigrated to New Zealand after winning the lottery.

A long-haired young man (sitting in the lotus position, with a dove perched on his hand and wearing hippy clothes) floats before Amy. He calls her Amelia, the girl of his dreams. Speaking in trippy rhymes he tells her she has all the tomorrows in the world and that once she has fallen down the kaleidoscope there is no way out of the dream. She asks if he is trapped and he replies that only she can save everybody for the Doctor has closed his eyes on the Octopus ride. The young man vanishes with a warning: 'Beware of the dark.'

The weather changes abruptly: it is cold, grey and rainy. The people on the promenade are now only stuffed dummies. Suddenly, Amy is confronted by five dark figures. They are wearing business suits and bowler hats and each carries a rolled umbrella. Their faces are set in manic grins and each is wearing psychedelic spectacles. Amy runs away from them onto the pier. She is watched by five figures in a candle-lit room. One of them is the young hippy and another is the Doctor. They want to help her but know they can only watch. One warns that if the dark consumes her she will cease to exist. Amy reaches the end of the pier as the five shadow men close in on her. They tell her that the more scared she feels, the stronger they will become. She replies that she is not frightened but one of them contradicts her, saying that everyone is afraid of the dark. Amy climbs over the railing and hangs above the stormy waves from which hands reach up as if to grab her.

As the shadows tell her that she must despair, Amy responds by thinking of ice cream. A cone appears in her hand and the happiness she feels causes the sun to break out and the beach to return to a summer's day. She climbs back onto the promenade as the shadows are dispersed by the sunlight.

Back in the room the men watching her realise she is stronger than any of them. The young hippy floats before Amy again and tells her that he used to be a musician in a rock band and that he used to visit Psychspace for his inspiration until it became harder for him to leave and he became stuck there with the other men: a painter, a poet, a mathematician and, now, the Doctor. Amy follows the musician into the room where she finds the Doctor comatose. She demands to know what these dreamers want from her. The musician tells her that when they lose hope the darkness grows more powerful and begins to consume Psychspace. Their only salvation is if Amy helps them to smash the glass and return them to reality. They ask her to sit down and dream.

Amy finds herself reverting to her childhood, watching an episode of Blue Peter on television. The Doctor is one of the presenters and he that she has to use her stubborn nature to transcend the metaphysical reality. Amy wakes up in the darkened room and tells the Doctor she can see something. He regains consciousness and asks what she can see. A large purple octopus is hanging from the ceiling above them. The Doctor recognises it as a psychic squid that has lured creative minds into its home dimension to feed on their psychic energy so that it can break into the real world and feed off human imagination. The squid/octopus wraps a tentacle around the Doctor and sends a shock of energy through him. The shadow men come down the stairs and then overpower the dreamers but they turn on the squid and use their combined power to cause it to explode. As the darkness closes in on them the Doctor urges Amy to imagine the TARDIS which she builds in her mind from jigsaw pieces. They run into the console room and shut the door.

Ivana explains that they are the Sisters of Purity and their twofold mission is to investigate the structure which has been in Earth space for a year, emitting exotic particles, while also finding out what happened to a similar party that disappeared six months earlier. When Novice Konami tries to contact the transporter ship that brought them it does not respond. They decide to make their way through the corridors to the command hub.

On the way they pass a large device that the Doctor says is a primitive attempt at building a time engine. He says it is leaking and is the probable source of the exotic particles. They come to a sealed door and the nuns decide to blow it open with explosives. The Doctor suggests using his sonic screwdriver instead. As he does so they are attacked by a group of robots. One of the nuns is shot while the others return fire. The Doctor gets the door open and runs into the command hub where he uses the computer to over-ride the security protocols and put the robots on stand-by mode.

There are human skeletons on the floor. The nuns think that they are the station's crew but the Doctor sees a functioning teleport and says that the crew left long ago. The bones belong to the previous investigation team. Ivana wonders how this can be: the sisters only arrived six months earlier but the bones look hundreds of years old. The Doctor feels stubble growing on his chin and says that the temporal experiment that went wrong has caused time to accelerate. This is why Konami couldn't contact the ship - it is in a different time zone.

At the mention of Konami's name, the nuns turn to look at her and see that she has aged tremendously. The Doctor says that time is passing at different speeds in different parts of the station. A small purple lizard runs over Amy's foot. The Doctor looks closely at it, saying that it looks familiar. As it scuttles away, the Doctor and Amy give chase, followed by the nuns. The corridor they run down has blossomed into a jungle and the lizard has already died of old age.

The Doctor tells the nuns that their only hope is to get to his ship. As they follow him through the jungle the plants turn blue and the TARDIS, when they reach it, has creepers and vines growing from it as well as screaming human figures bursting from its outer shell.

The Doctor says that the TARDIS is caught in an accelerated time field. Amy recognises the faces on its shell as Cosette (DWM 430-431) and Margaret (DWM 432). The Doctor also recognises the Shasarak (DWM 424). The figures coalesce into a giant ogre/TARDIs. The nuns open fire but the monster flings energy balls at them and catches hold of Konami, absorbing her into itself. Only the Reverend mother, Sophia and Bridget survive the assault as the monster races away, leaving the TARDIS behind. The Doctor and Amy enter the TARDIs while he berates himself for failing to recognise the jungle as that from the planet Basingstoke (DWM 421-423). He says the TARDIS has been infected and absorbed life forms wherever they have gone. The temporal acceleration has allowed the tissue to evolve into autonomous life which has now been expelled, resulting in a half human, half monster, and half TARDIS hybrid.

The nuns corner this monster but as they open fire it 'vwarp-vwarps' away. They decide to destroy the time engine that they passed earlier as an insurance against time disruption.

The Doctor tells Amy to stay in the TARDIS because the chances of premature ageing are so high but she insists on accompanying him on his mission to the teleport where he intends to lure the creature and reconstitute its individual parts. He draws the creature to him with the sonic screwdriver and then locks it into the teleport. While he sets the machinery in motion the nuns return and take Amy at gunpoint. They demand to know what he can tell them about time technology but, instead, he says he knows that they have been fighting a war against androids that look human. He says he has worked this out because Sister Bridget has not aged visibly, unlike the others.

Revealed as a spy, Bridget kills Sophia but Ivana returns fire, shooting off Bridget's face to reveal the android beneath. The Doctor shuts the teleport chamber door. Amy points out that they are now trapped inside. Ivana use the time to tell them that humans have been fighting a thousand year war against Galatean robots: 'the heresy of metal'. As she does so, the robots in the chamber are reactivated by Bridget interfacing with the computer. Ivana destroys them with her last three sonic grenades. However, Bridget has an army of robots gathering outside ready to break in with laser torches.

The only means of escape is the teleport but that would mean stopping the creature's reconstitution (thereby killing it) and there are two hours before the process is finished. Amy tells the Doctor she doesn't feel well. As he looks at her she ages visibly in front of his eyes.

The Doctor has to support Amy so that she can stand up. He tells her that she must have walked into the accelerated time field. She asks him if he can make her young again. Ivana says that she is going to kill the creature in the teleport so that they can use that way as a means of escape. Amy angrily retorts that the creature is made of innocent people including Sister Konami. Ivana says that Konami will be a martyr to the cause. Amy lunges at her, saying that it is murder but before Ivana can shoot her the robots burst through the door. The Doctor drags Amy away while Ivana shows the robots a detonator switch in her hand. She has rigged the time machine at the heart of the space station with explosives: if the humans can't have it, neither will the robots.

The robots open fire on her. As she dies, Ivana says she is going to heaven while the others are condemned to hell. She clicks the detonator switch. As the time engine explodes the Doctor drags Amy towards it. He says that the accelerated time energy will kill them in seconds unless they get to the eye of the storm. They shelter beside the engine until the jungle around them has aged, died and withered away. They re-emerge to make their way back to the control room. On the way they are stopped by two robots who take them to Sister Bridget. She says that she has seen the light: they have been blessed by a divine incarnation.

A glowing blue girl emerges from the teleport. She is the little girl that the Doctor and Amy saw at the Shining Dawn (DWM 425-428). She says that Amy saved her and the Doctor made her. The Doctor says that it was an accident; she is the combination of several young women, a couple of monsters and the TARDIS. Bridget calls her the ultimate expression of being (flesh and machine combined). The girl responds by disintegrating all of the robots with a wave of her hand.

The Doctor offers to help her but she says that she doesn't need his help. She is Chiyoko, the daughter of a thousand generations. She can see both history and the future. The Doctor begs her to help Amy who has now aged into a decrepit old woman. Chiyoko declines, saying that they have had their time and would only try to stop her. She "Vworp"s away.

In a flash of inspiration, the Doctor carries Amy into the teleport and uses his screwdriver and Bridget's bio scanner to retrieve Amy's body patterns. He restores her to her youthful self. The space station begins to explode around them so they teleport back to the TATRDIs and dash inside. As the station detonates the Doctor sets the controls so that the TARDIS can follow Chiyoko through the vortex. He says that this is only the beginning of their adventure.

The Doctor says that the TARDIS is caught in an accelerated time field. Amy recognises the faces on its shell as Cosette (DWM 430-431) and Margaret (DWM 432). The Doctor also recognises the Shasarak (DWM 424). The figures coalesce into a giant ogre/TARDIs. The nuns open fire but the monster flings energy balls at them and catches hold of Konami, absorbing her into itself. Only the Reverend mother, Sophia and Bridget survive the assault as the monster races away, leaving the TARDIS behind. The Doctor and Amy enter the TARDIs while he berates himself for failing to recognise the jungle as that from the planet Basingstoke (DWM 421-423). He says the TARDIS has been infected and absorbed life forms wherever they have gone. The temporal acceleration has allowed the tissue to evolve into autonomous life which has now been expelled, resulting in a half human, half monster, and half TARDIS hybrid.

The nuns corner this monster but as they open fire it 'vwarp-vwarps' away. They decide to destroy the time engine that they passed earlier as an insurance against time disruption.

The Doctor tells Amy to stay in the TARDIS because the chances of premature ageing are so high but she insists on accompanying him on his mission to the teleport where he intends to lure the creature and reconstitute its individual parts. He draws the creature to him with the sonic screwdriver and then locks it into the teleport. While he sets the machinery in motion the nuns return and take Amy at gunpoint. They demand to know what he can tell them about time technology but, instead, he says he knows that they have been fighting a war against androids that look human. He says he has worked this out because Sister Bridget has not aged visibly, unlike the others.

Revealed as a spy, Bridget kills Sophia but Ivana returns fire, shooting off Bridget's face to reveal the android beneath. The Doctor shuts the teleport chamber door. Amy points out that they are now trapped inside. Ivana use the time to tell them that humans have been fighting a thousand year war against Galatean robots: 'the heresy of metal'. As she does so, the robots in the chamber are reactivated by Bridget interfacing with the computer. Ivana destroys them with her last three sonic grenades. However, Bridget has an army of robots gathering outside ready to break in with laser torches.

The only means of escape is the teleport but that would mean stopping the creature's reconstitution (thereby killing it) and there are two hours before the process is finished. Amy tells the Doctor she doesn't feel well. As he looks at her she ages visibly in front of his eyes.

The Doctor has to support Amy so that she can stand up. He tells her that she must have walked into the accelerated time field. She asks him if he can make her young again. Ivana says that she is going to kill the creature in the teleport so that they can use that way as a means of escape. Amy angrily retorts that the creature is made of innocent people including Sister Konami. Ivana says that Konami will be a martyr to the cause. Amy lunges at her, saying that it is murder but before Ivana can shoot her the robots burst through the door. The Doctor drags Amy away while Ivana shows the robots a detonator switch in her hand. She has rigged the time machine at the heart of the space station with explosives: if the humans can't have it, neither will the robots.

The robots open fire on her. As she dies, Ivana says she is going to heaven while the others are condemned to hell. She clicks the detonator switch. As the time engine explodes the Doctor drags Amy towards it. He says that the accelerated time energy will kill them in seconds unless they get to the eye of the storm. They shelter beside the engine until the jungle around them has aged, died and withered away. They re-emerge to make their way back to the control room. On the way they are stopped by two robots who take them to Sister Bridget. She says that she has seen the light: they have been blessed by a divine incarnation.

A glowing blue girl emerges from the teleport. She is the little girl that the Doctor and Amy saw at the Shining Dawn (DWM 425-428). She says that Amy saved her and the Doctor made her. The Doctor says that it was an accident; she is the combination of several young women, a couple of monsters and the TARDIS. Bridget calls her the ultimate expression of being (flesh and machine combined). The girl responds by disintegrating all of the robots with a wave of her hand.

The Doctor offers to help her but she says that she doesn't need his help. She is Chiyoko, the daughter of a thousand generations. She can see both history and the future. The Doctor begs her to help Amy who has now aged into a decrepit old woman. Chiyoko declines, saying that they have had their time and would only try to stop her. She "Vworp"s away.

The Doctor tells Amy that they cannot stop her without causing a paradox. They try to follow her to her next destination but the navigation systems 'go all wibbly' when they follow her time stream. They arrive in a devastated city. The Doctor gives Amy some pills to counter the effects of high levels of radiation while they explore. They stumble across the ruins of St Paul's Cathedral and realise that they are on Earth, albeit long after Amy's time.

A ship attacks them, firing energy beams. They try to get back to the TARDIS but a near miss buries the TARDIS under tons of rubble. Galatean robots close in on them but are disabled by an E-M burst from a party of human soldiers. Captain Kaido orders the incineration of the robots while she questions the Doctor. He tells her that they dropped in from one of the orbital stations. She isn't much interested but, once she has ascertained that they are organic she takes them to the crypt beneath St Pauls. Kaido takes them down in a lift. Riding with them is Sergeant Sokkuri. She was rescued by Kaido after her ship was shot down by Galateans.

They enter a chapel containing a massive statue of Chiyoko. Amy and the Doctor pretends that they are Chiyoko worshippers, too, while realising that she must have beaten them to Earth by several centuries. They continue on into the bunker control room. On a screen, the Galatean Prelature is contacting Earth. It offers the humans mercy in the name of Chiyoko. Commander Hachiman is furious that they name Chiyoko. The Galateans make an offer to the last humans: they can keep the planet as a reservation while the robots take the stars. Hachiman refuses, saying that humans would rather die than surrender.

Hachiman asks one of his men if the Ultimate Weapon is ready. He is told that the work of ten years has been completed and tells Kaido that she knows what to do. The Doctor and Amy follow her to a locked room. She tells them that they are in a restricted area but the Doctor says that he only wants to see what she is doing and to prevent it. She tells him that he is too late. She has already started the countdown and the computer only responds to her brain pattern. The Doctor sees that a network of fusion bombs has been panted beneath the planet's surface: they are going to destroy the Earth.

Kaido pulls out a gun but before she can shoot she is killed by Sokkuri. The Doctor scans Sokkuri and finds that she has a Galatean brain. Sokkuri tries to absorb the dying Kaido's brain patterns but an emergency E-M burst from the control room kills her. The countdown has reached 49 when Chiyoko materialises. She says that it has been fun playing a game of Galactic War just to see who would win but now that the Galateans have proved their superiority they can continue while the humans must go away. She says goodbye to the Doctor and Amy before dematerialising.

Amy asks the Doctor if he can do anything to stop the count, which is on 25. He says there is a remote possibility and then the planet explodes.

The Doctor and Amy find themselves lying on the grass of an English village green. The Doctor says he would remember stopping the planet from exploding so he assumes it must have. Amy wonders if they are in heaven. They ask a passerby for directions and the Doctor recognises him as the scientist Alan Turing. Turing assumes that he knows the Doctor from Oxford and invites them back to his home. He tells them that they are in Wilmslow in 1954. Over tea Turing and the Doctor discuss Turing's work on Fibonacci numbers. When the scientist goes to fetch some of his papers, the Doctor whispers that something is wrong: Turing should have killed himself the previous month. He asks Amy to step outside while he and Turing are getting on so well. Turing has overheard this conversation. This prompts him to want to learn more (as well as assuming that the Doctor is homosexual like him). He tells the Doctor that he had considered suicide but was saved at the last moment by a small Japanese girl called Chiyoko. Turing admits that he has been in Wilmslow in 1954 ever since he can remember.

Amy, meanwhile, finds herself following a dodo through the countryside after it drops a parchment. It steps through a hole in space and she follows it. It leads her into the library of Alexandria where John Keats and Buddy Holly are writing a musical for Jayne Mansfield. They are interrupted when Galatean robots arrive and blast Keats, Holly and Mansfield to pieces, revealing the trio to be robots. Amy escapes the destruction only to find herself at gunpoint again.

The Doctor uses his sonic screwdriver to open a hole in the fabric of space and he and Turing step through to a vast hall containing huge spheres. Each is a dimensional projection of various places at different points in Earth's history (including the Globe Theatre, Stonehenge, a pyramid and Easter Island). The Doctor says it is an abandoned museum. They walk across a gantry to where Amy is standing with the heavily armed Bronte sisters. Amy reveals that the sisters, and Turing, are robots. The Brontes add that they are being stalked by Galateans. The Museum of Lost Opportunities was built as a memorial to the human race in the middle of an asteroid belt around a dying sun. It was designed by Chiyoko and is all that remains of Earth. Now that the Galateans have wiped all life from the galaxy they have sought out the museum.

Emily Bronte is destroyed by a Galatean robot but Charlotte and Anne fight it off. Charlotte says that their decaying programs allowed them self knowledge. They know they are robots but believe they have as much soul as living creatures. They take the Doctor to a time scoop which they used to bring the Doctor to them. They say that they need the Doctor because he is the only one with enough knowledge of changing history to safely remove the Galateans from time before they can be created. The Doctor points out that this will end the Bronte robots' existence but they say they are aware of that.

A group of Galateans burst in and destroy Anne Bronte. As Charlotte fights back the others take cover. Amy asks if they can get the time scoop to bring the TARDIS to them but the Doctor says they will be killed by the Galateans before they can get to the controls. Charlotte says that it is time to bid goodbye...

Back on Earth in the near future a falling star brings an infection that spreads rapidly, soon becoming a pandemic. Robots travel the land, identifying new victims and sterilising the derelict towns with a circle of fire each with a radius of one mile for every new case found.

The Doctor, Amy and Turing are sent back by Charlotte Bronte, arriving amidst the devastation. Turing says that this is the time of the creation of the Galateans. He says that the history books need to be rewritten or this is the end of humanity. The Doctor explains that it is not so simple: this is the time before Chiyoko's interference began. Before he can elucidate further, they are confronted by one of the robots. It says that contaminated life forms must be sterilised but their presence is noted by humans in an underground facility. The robot detects that they are not contaminated and takes them to the facility. The Doctor tells Amy that he is rather vague on this time period but is surprised that a cure has not been found. The trio are taken to Keltor Jacobs. He introduces himself as the last hope for the human race. He tells them that the Doomsday Plague has all but wiped out the human race and the research stations across the empire are going out one by one. His assistant, Chloe, says that they have spent five years looking for n alternative solution and have settled on the creation of Galateans: robots containing the uploaded minds of the human race. Turing tries to tell them that the Galateans are not the solution but the destruction of humanity. He says that the duplicates will come to believe that they are the originals and will wipe out the humans believing them to be imposters.

Chiyoko materialises among them and makes it that the three newcomers were never there. Like phantoms, they have to watch as Chloe activates the Galateans just three hours before Research Station Minerva reports that it has found a cure for the plague. Jacobs tries to recall the Galateans but they have already started killing the humans. They tell Jacobs that humanity is weak and vulnerable and that now is the time of the Galateans. Jacobs tries to abort the Galateans with an EM pulse but Chiyoko kills him.

The Doctor says that she is diverting the course of history to ensure her own creation. She turns to him and agrees that playing with time is fun. She takes them to the planet Kepler IV, one thousand years later, to witness the glories of war. The Doctor asks her how she can enjoy standing on a battlefield, watching two armies annihilate each other just so that she can come into being. She turns to him and tells him that he made it happen by creating her.

The Doctor tells her that the Galateans wipe out all other life in the galaxy and begs her to put things back the way they were. She tells him that such an action would mean giving up her own life and that she has as much right to exist as anyone else. He tries to argue that if her existence depends on the obliteration of everybody else then she should give up her life. When she says she has no pity for the dead he tells her that he can have no pity for her. He asks her to remember that he gave her a chance.

She tells him that he is funny and that it is time for him to go away. She puts the Doctor, Amy and Turing back in London on the day that Earth was blown up. The Doctor says that they have been brought here to die and comments on how tidy it is to end this way. Amy screams as a ship hovers towards them, blasting at them with laser canons.

It turns out that the ship is actually shooting at the earlier versions of the Doctor and Amy as they scramble across the rubble. The Doctor decides that this time they can escape the same way that they did the last. He, Amy and Turing follow the same route into the ruins of St Paul's. The Doctor adjusts a rifle to nerve paralysis setting and shoots two guards. They then find their way into the bomb control room and hide. This time, the Doctor shoots his and Amy's earlier versions, knocking them out, so that when the time scoop picks them up he can greet the Bronte sisters and readjust the time scoop to bring Turing along, too. He then puts their past selves into the Wilmslow time bubble to meet the earlier Turing.

Chiyoko materialises among them and threatens to wipe them from history. The Doctor says that this isn't a safe option for her and scoops up Cosette, Margaret and Konami from before they were absorbed into the TARDIS. He then wipes the coordinates so that Chiyoko won't know where they came from, or when. That way, he says, her own existence will be under threat if she takes any drastic action. Amy whispers to Turing that she doesn't follow any of this. He replies that it is a bit beyond him, too.

Chiyoko is overcome by pain and regret as she feels empathy for the first time. The Doctor asks her to unwrite her own existence. She admits she is scared and, sobbing, sends her component lives back to the places they were last in before they were absorbed.

Amy notices that the universe is growing dark; the Doctor says that it is being erased as it ceases to exist. He time scoops the TARDIS to them and sets the controls for Keltor Jacobs' laboratory just after the Galateans are awoken. He tells them that the cure for the Doomsday Plague is about to be announced. Turing calls the Galateans as they awake on Moonbase and tells them that he is the last of the Galatean race. He sends them his memory files so that they can see a future that must never exist, thus averting the war. He hopes that the organic and artificial humans can live together in harmony.

As they are walking near the Acropolis they see an old woman, Calidora, trying to stop some soldiers. They have a gold statue of Athena on a cart. She tells them that if they destroy the statue as they intend, then Athens will be destroyed in turn. They brush her off and go on their way. Amy helps Calidora to her feet. The woman tells her that they intend to melt the statue (taken from the temple of Athena at the Acropolis) to fund the war with Sparta. She says that the wrath of the gods will be swift. She presses something into Amy's hand as thanks for her kindness, adding that they should flee the city.

The Doctor follows Socrates to the tavern, watching as the old man is abused by passers-by. In the tavern, Socrates (now very drunk) apologises for punching the Doctor. The Doctor turns to the youth who is Socrates' only disciple and asks how this happened. The youth, Plato, says that Aristophanes' play, "The Clouds", portrayed Socrates as a fool and since then and the populace started to treat the real Socrates as if he were the fictional character. Since then, Socrates has turned to drink.

No sooner has the statue been melted in a workshop than thunder echoes around the city. Citizens are struck by bolts of lightning and others flee in panic. Amy stops to pick up a toddler in the street and she is also struck by lightning. A giant face appears in the sky and its booming voice announces itself as Zeus. It says that the people of Athens have betrayed its trust and they shall pay in blood.

The Doctor runs up to the Acropolis, pushing his way through a tide of people going in the opposite direction. Plato follows him. He shouts up to the face of Zeus, hovering above the building, asking it to stop killing people at random. When he gets no response he tells Plato that the image is powering down. It promptly fades away.

Rory gets to Amy and finds that both she and the child are safe. She returns the child to his grateful mother. The people around the city are declaring that they are damned and should start slaughtering goats as sacrifice as soon as the sun rises. One man pours all of his wealth down a well; others decide to burn the libraries because enlightenment has been their downfall.

The Doctor and Plato return to the tavern and reunite with Rory and Amy. The Doctor lists the possibilities for what is happening: aliens who arrived centuries earlier were mistaken for gods; aliens who have just arrived are posing as gods. Socrates tries to interject but the Doctor brushes him away and insults him. Amy drags the Doctor outside to find out why he is being so rude but the Doctor tells her that Socrates wrote nothing in his lifetime, everything that is known of him was written by Plato, and Plato is the real genius. Amy says that she knows what it is to be let down by a hero. She adds that she grew up and got over it. The Doctor returns to the tavern and asks what the first question is that they should ask. Socrates replies that they need to find out why this is happening now. The Doctor asks if anybody has seen anything unusual.

Rory tells him about Calidora and the statue. Amy produces the talisman that Calidora gave her. The sonic screwdriver shows that it is able to absorb a lightning bolt. He tells Plato to take Amy and Rory to Calidora's house while he and Socrates search Athens for more of the metal. As they go, Zeus appears to power up again. However, when they reach Calidora's residence, the woman is dead with an empty cup of hemlock beside her.

In the city, a tree takes on the shape of a cyclops and attacks the soldiers that took the statue of Athena. Harpies erupt from the ground, a three-headed dog made of water leaps from a well and a wall becomes a griffon. All of them shout that they are made "for the glory of Zeus". The Doctor follows a signal to the forge where the statue was melted. As the Doctor and Plato look on in horror, a nine headed dragon bursts from the pool of molten gold telling all mortals that they will die for the glory of Zeus.

The Doctor recognises that this is the Hydra, fashioned from burning coals. He asks Socrates to throw him a poker and uses it to strike the talisman that Calidora gave Amy. Not only does the Hydra disintegrate but so do all of the other monsters in Athens. The Doctor tells Socrates that he shorted out the psychokinetic energy by using the poker which was made of the same metal as the talisman.

Elsewhere, in Calidora's chamber, Plato reads a letter that Calidora left. It tells how, as a little girl, she saw a fireball drop from the sky. When she found where it landed she saw that it was a golden egg. The egg commanded her to bury it in the most sacred of places, which she did. However, she kept some of the molten metal and poured it into the statue of Athena that her father was making and then used more to make the talisman. Amy tells all of this to the Doctor and he and Socrates run to the temple of Athena. The Doctor finds that the egg is hidden in a dimensional fold above the temple. It has grown to a huge size. Socrates tells the Doctor that it was fed on belief and if they believe then they can enter. They touch the surface of the egg and are pulled inside. They arrive in Olympus.

The ancient gods are bowing before the wrath of Zeus. He is angry that they have let their worshippers grow less ardent. The only god who has not failed him is Ares. The Doctor steps forward to intervene but Zeus chains him to a pillar with a sweep of his hand.

In Athens, the armour of countless soldiers is swept into the air to join together as a giant: Ares. As Alexios and his men race to combat the giant he cuts them down with his huge sword while simultaneously declaring war.

Hanging upside down in his chains, the Doctor tries to tell the gods that they are merely psychic constructs created by a woman who is now dead. Her death has led to them running out of control. Socrates whispers to the Doctor that telling somebody they are not real may take some believing. The Doctor says that Socrates might be the very man to convince them.

The soldiers fall back from Ares assault. Plato tells them to assemble in the main market square: the Doctor and Socrates were expecting this and have a plan. Amy rides up to Ares on a white horse and challenges him before leading him back to the square. Meanwhile, Socrates uses a series of logical questions to lead Zeus through the argument that: Zeus is all powerful; he therefore has absolute knowledge; his knowledge includes events in the future; he saw that men would one day disrespect the gods; this day was therefore predestined; Zeus must obey destiny; his power cannot be absolute.

As Ares arrives in the square he is challenged by 'Roranicus'. Ares uses his massive sword to smite Rory who has a blade fashioned from the psychic gold. Ares blade shatters and Rory uses the sword to cut off the god's leg and hand. The other soldiers and people of Athens wade in and smash Ares.

When Zeus witnesses the defeat of his son Socrates asks whether a god can fall to a man. If he can't (as Zeus insists) then neither Ares or, by extension, Zeus can be true gods. Zeus disintegrates, the gods vanish and Olympus begins to collapse. Athena, goddess of wisdom, remains briefly. She knew the truth all along. She asks the Doctor a question: "What is buried in man?" as she fades away the Doctor follows Socrates out of the portal and back into Athens. He holds a piece of golden metal that literally builds gods. He says he does not know who unleashed it or made it but he would love to find out.