Harry Winter hates his job working on the farm for his father. Life has been hard since his mother died. The long October afternoon is spent scouring the farm for rocks to mend the walls. He goes out to a pile of rocks, Lucifer’s Tombstone, on the outskirts of the village. Nobody can remember why the cairn is so called. He trudges through the mud at sunset. The mound isn’t as large as he remembered as he piles the rocks into his wheelbarrow and he soon reaches the bottom of the pile. The ground beneath his feet starts to shift and a hand thrusts through the soil. A second hand claws its way out. A creature reeking of decay rises and laughs at him and Harry realises that this is going to be his last day on Earth.

The Doctor wakes with a start. His head is aching and his vision is blurred. He can’t remember what has happened. He is pinned to the floor by a pair of strong hands. A fire burns behind his head. His vision clears and he sees seven men looking down at him, their clothes reminiscent of eighteenth century Earth. One of the elders announces that the demon has risen.

Three weeks have passed in Thornton Rising since Harry died and the sun has not risen once in that time. Abraham Godchild rides to the village. News of the village’s darkness reached London a week earlier and he has been dispatched to investigate. If the matter is found to be the work of the Devil the village will be removed from every map. As far as the king is concerned the village will have never have existed. Adam is tall, fashionable and rich. He has proven himself to be loyal and dedicated. A shiver runs down his spine as he feels that something in the shadows has lured him in. something alien. He peers around through the night but he can see nothing of the village except for a tall blue wooden box.

The Doctor demands to know how he got there but he is met by a barrage of questions and accusations. He can tell that his captors are terrified of him. More voices spill out demanding to know where he came from and what he is. A single voice rings out and all the others are silent. It orders the men pinning him down to leave him alone. A woman speaks again, asking to see him. She walks through the crowd that separates for her. She is young and confident, dressed simply in a brown gown. He guesses that her slim figure and clothes put her in her early twenties. She studies him carefully. An old man tries to step between them, addressing her as ‘Charity’. He asks her to go home sand lock herself away but she refuses, saying that the Doctor is not what they believe. She says she is disappointed that he is not a demon. The Doctor wonders why they think that of him and is told by a man in the crowd that he is not someone they recognise, nor has anyone else been reported arriving for over a month. Someone else asks him to explain his strange clothes. He tells them that Janis Joplin gave him his coat but someone else comments that they are unnatural. Charity responds that all clothing is unnatural and that there is no evidence to suggest that he is not an angel, a demon or an ordinary man. The Doctor, perplexed, says that he is there to help. He denies being a demon and says he is the Doctor. They want to know how he came to be on the moors but the Doctor tells them that amnesia is a tricky thing. There might be a reason for his forgetting. An old man, Tully, says that they do not want to be mocked so the Doctor casts his mind back and tries to remember what happened to him.

He remembers travelling alone from the Acropolis and landing on Earth. He stepped into the rain of the Yorkshire Dales. He remembered the rain the last time he saw Donna and wrapped his coat round him. The night was black and cold. There were no stars, which struck him as odd. He smelled the air and guessed that he was in the seventeenth or early eighteenth century. A hand wrapped itself round his shoulder and frosty breath touched his neck. He suddenly found himself in somebody else’s mind. He was looking out through someone else’s eyes – a killer – and saw the last moments of Harry Winter’s life. In the reflection of Harry’s eyes he saw a dim image; pale skin and bared fangs. Then the Doctor sees another man riding across the moors to his death. He realises that this is not a memory but something in the here and now.

Abraham Godchild hears a woman’s voice in the void around him. The air grows colder around him. The voice calls for help, a woman in trouble. Godchild leaps from his horse. He follows the voice down a slope and sees a woman clinging to the grass. She is tall and slender, unnaturally thin. He reaches for her and hauls her to him and onto the path. Then he slips and they roll over into the mud. She thanks him, smiling wickedly. She has long blonde hair and pale, translucent skin. She is more than beautiful, captivating. She forces her way into his mind and he obeys her without question as she sighs for him to dance with her. The mist rolls in around them.

Clouds blot out the Doctor’s vision and he finds himself in the tavern, alone with Charity. She asks him to tell her everything. He asks why everyone is so on edge. Why everyone is so suspicious of him. She tells him that the village has been cut off for three weeks and that food is running out. Cattle are being found ripped apart in the fields and people are going missing: men are lured onto the moors and found dead – ripped apart, too. Women are vanishing as well but their bodies have never been found. She tells him that he is the only man they have found alive which is why they think that he is the demon. The men who found him were hunting the demon. He wonders about the darkness and the absence of stars. Charity says that the sun failed to rise one day and it has been dark ever since. She says that some people thought they could see a glimmer of sun and walked towards it but ended up coming back to the village from the opposite side. The Doctor wonders about a recursive occlusion.

Charity, embarrassed, explains that she thinks that there could be another world out there, hidden. It reminds her of when she was younger and believed in fairies. She remembers something that the Doctor said about the universe and asks him what he meant.

The rain drizzles on Godchild as he dances with the demon outside the village. Their thoughts are entwined and he feels at ease. He remembers dancing with Miss Emily Wainwright at court balls. The creature encourages him to think that she is Miss Wainwright and he is content to dance forever. The creature buries her fangs in his neck. He crumples to the floor. The creature stands above him, remorseless. He dies pretending that she really was Emily.

Charity tells the Doctor how Harry Winter was the first to disappear. The Doctor asks what Harry had been doing and she says that some people think he disturbed an unmarked grave; Lucifer’s Tombstone. She laughs it off but the Doctor leaps to his feet and demands to know more. He bounds out of the door looking for someone who can help him. A crowd of villagers are waiting outside in the rain. A young man bursts into the crowd and Charity runs to him and they fall into an embrace. Charity introduces him to the Doctor as her husband, Nate. The two men greet each other coolly.

The Doctor asks the crowd if anyone can shed any light on this mystery. An old man makes his way forward. He tells the Doctor that there is a story of a similar darkness that lasted seventy days. It was banished by the Sisterhood and an abbey was founded to commemorate the victory and the village grew up around it. The Sisters are long gone.

The Doctor silences the crowd so that they can hear a noise approaching; the thudding of horse’s hooves. A black steed bursts into the square. Bound across its saddle is a corpse. The Doctor turns out the dead man’s pockets until he finds a letter that bears the name ‘Abraham Godchild’. The letter details the world’s knowledge of the disappearance of Thornton Rising and Godchild’s quest to penetrate the darkness. Nate suggests that Godchild was killed by wolves but the Doctor disagrees. He points out a pattern of blood on the man’s chest and rips the shirt away to reveal, written in the dead man’s blood, the words ‘I AM NOW’. The Doctor surveys the village. He feels a tingle in the air. He says that something is out there, waiting. He says that the corpse has been drained of blood and that means that something in the dark feasted on him and that it was a creature from beyond the stars.

He finds himself in the creature’s mind again. It was dark and cold and the creature was panicking, trapped. Then Charity calls him back to himself and he realises that the whole thing fits. He says that there is a creature out there, feasting on the iron in people’s blood. It had been buried in iron-rich Yorkshire ground, overwhelming its systems for centuries until it was released accidentally a few weeks ago. Only Charity understands that the Sisterhood buried the creature to banish it. He guesses that the creature is out for revenge. And that he bumped into it on the moor. He tells Charity that the creature must have got into his mind, hence his amnesia but he still can’t explain the darkness.

Charity and the Doctor make their way to the Abbey. She has never been this far out of the village in the dark. They circle the Abbey. Its structure is so varied that it looks odd. The towers are different heights and the windows are asymmetrical. He thinks that it looks like a second building has been built on top of another. Charity wonders if the remaining friars can explain this discrepancy.

The Doctor uses his sonic screwdriver to open the doors. Inside, the building is in darkness. Charity feels a sense of inexplicable dread. The Doctor leads her up a staircase into a tower. The walls seem to be humming, and she realises that it is the screwdriver at work. The Doctor disagrees, saying it is alien technology at work. His voice is cut off as the bells in the tower begin to toll wildly. Charity stops, frozen. She says that the bells stopped ringing when the darkness came. He hauls her up the stairs to the bell chamber. As they arrive at the top the bells are silenced. They step through the door into a moonlit room. A vile stench hangs in the air; decayed human flesh. They cross to the bells where two dead monks lie, their faces contorted in horror. Their bodies are strapped to the bell ropes.

Suddenly, one of the monks speaks. He says it was a warning, for them, but for the others it was a call to war. The monks begin to ring the bells again. The Doctor realises that the bodies have been reanimated to keep him at bay. Charity screams, pointing into the night. A figure is coming across the moor, its eyes shining with blue light as it passes through the mist. The demon of Thornton Rising has returned.

The Doctor and Charity flee down the steps into the garden. The Doctor explains that the monks were drained of blood and kept alive as playthings. He asks if Charity is scared, delighted when she says yes because it keeps her alert. He drags her with him to Thornton Rising. The village square is empty apart from Godchild’s horse. He calms the worried beast, which he calls ‘Henry’. He explains his plan: he needs three ore horses. He asks Charity if she can ride, but she says no. he wonders where he can get more horses and Charity tells him that Nate is a blacksmith. He tells her to lock herself away until everything is over and only answer the door to him.

Charity locks her door after watching the Doctor ride away to the stables. Then she looks out to the field. She wonders why she had let the Doctor go so easily and dismisses all of her childish fears. She runs after the Doctor through the village. When she arrives in the muddy fields the Doctor is already gone. She arrives at the stables. Nate tells her that the Doctor has already been and gone, taking three men with him, saying he was going to fight the demon. She kisses her husband briefly and then runs out towards the distant glow in the night.

Owen Grantham, Patrick Higgins and Wesley Millet follow the Doctor across the dales in silence. Their horses protest as they cross the muddy fields. The men and beasts are uneasy, unnerved by the Doctor’s lack of fear. They arrive in a wood and the Doctor reins in his horse as a thin figure stands alone with her back to them. The Doctor signals them to be silent and approaches the woman. She spins to face them, and greets the Doctor.

The Doctor tells the men to close their eyes and try not to listen to her. The woman watches as the men encircle her. She seems worried by this, asking if the Doctor thinks he is clever. He explains that the horseshoes are made of iron and that the men are safe if they stay on their horses. He tells them that she is a being of purest darkness. She tells them that she is a Baobhan Sith, a race that perished in a long ago galactic war. She fled, the last of her kind, banished to the Earth. The Doctor finds himself back in her mind.

The thoughts were of a struggle aboard a shuttle craft. Sparks erupted, Baobhan women screamed and the craft plummeted towards the ground. The Doctor wrenched himself free of these thoughts and found himself back in the woods with the men. He wrenches himself from her mind. The woman explains that her ship was devastated on planet-fall with only a handful of survivors. There was no technology to repair the ship so the women fed on the local life. The Doctor asks what went wrong and how he got inside her mind. She replies that this was her plan – keep her friends close and her enemies closer. The Doctor laughs this off. She says that the Sisterhood vanquished the women and slaughtered them until she was alone, then trapped her where she slept and buried her alive for centuries. This, she says, was a big mistake.

The Doctor reflects on his own loneliness and offers to find the last Baobhan Sith a new home. She smiles, saying that the Doctor will provide her with the chance for revenge on the people of Earth and rebuild the Baobhan Empire. The Doctor asks how this will happen if she continues to kill all of the men on the planet. A twig snaps and footsteps approach. A dozen women emerge from the mist; some young, some old, their corpses bloodstained. The Doctor mutters about parasitic DNA as the women call for the horsemen to dance with them. Muttering that the corpses are beautiful the three men dismount and the women rip them apart with their fangs in a hedonistic frenzy. The Doctor sees another woman watching all of this from the edge of the clearing: Charity. She steps forward and he sees her gown, soaked with blood. She smiles at the Baobhan Sith saying how alive she feels. The Doctor says that all she feels is death but she disagrees. Her eyes burn brighter at her sudden knowledge of the universe as seen through the eyes of the alien. She eulogises about the colours, music and worlds that she has never experienced before. Then she asks the Doctor what happened to his planet. She asks the Doctor to dance with her but the Baobhan Sith interrupts; she wants to get her revenge on him personally.

She says she recognised his type when she first entered his mind. She knows the Time Lords and that her kind has feasted on them once before, long ago when they were in their infancy. He retorts that the Time Lords defeated the Baobhan Sith back then. As he does so he notices the women edging closer to him. He tells them that they can’t lay a finger on him while he is on the horse. The Baobhan Sith points out that it is Godchild’s horse and that the shoes are made of silver. The Doctor sighs as the alien smiles. He pulls on the reins and rears the horse. He whistles loudly to call one of the other horses and leaps across onto its back. He gallops back to the village through the mist.

The mob is gathered in the village square, demanding answers. The Doctor calls for quiet and tells them that something is coming and that they will only be safe if they do what they are told; lock themselves away and use iron to defend themselves while he ends everything. Some villagers say they want to fight but a rumble sounds all around them and lightning shoots out of the abbey into the clouds, the lightning forks and falls into a dome around the village. The Doctor realises that it is a force field around the village.

A living, glowing fog rolls in. Some of the villagers barricade themselves into their homes but others return to the square with pitchforks. A circle of blue eyes forms on the edge of the mist, surrounding the villagers. One of the creatures bursts into the square and knocks a man to the ground. It kills him and feasts on his body. The sound of hooves approaching heralds the arrival of the Baobhan Sith on Henry. She orders that all of the men are to be purged from the Earth. The men shrink back but the Baobhan women close in and the screaming starts.

The Doctor hears the cries as he approaches the abbey. He wonders why people don’t listen to him. The abbey door bursts open, revealing a cowelled figure that the Doctor takes to be the Abbot. The figure welcomes him in with a gesture. He follows a signal from his screwdriver to the crypt.

Back in the square the Baobhan Sith is dragging out the deaths of the men as they scurry around in the mist. She is enjoying their fear, sending out her sisters to pick off the men one by one. Nate is there, searching for Charity. He finds her but she has changed almost beyond his recognition. She tells him to dance with her.

The Doctor examines the crypt. It is dark and damp. The walls are smooth, not stone, humming with the energy of a spaceship on standby. He finds a door and uses his screwdriver to unlock it. The flight deck is revealed, charred and devastated. He tries to coax a panel back to life and sees that one has been activated recently. It shows a force field has been created to keep people in the village. He finds that it also keeps out ultra violet light to protect the Baobhan Sith. He knows that if he switches it off it will kill the women. He hesitates, not wanting to commit murder but the sounds of a scream from the village prompts him. He presses the controls to remove the shield. However, as he runs from the abbey he realises that it is still night and that the slaughter is still going on in the square.

The Baobhan Sith hears him coming through the fog. When he tells her that the shield has been lifted she orders all the men to be killed at once. The Doctor orders the men to run east. As the alien tracks him down the Doctor holds her off with a pair of wrought iron door handles. As the sun rises one of the women bursts into flame. The alien reminds him that he is ending her race for ever as her skin boils and her flesh smolders. With her dying breath she tells him that his time will be over too, sooner than he thinks. He turns away, unable to watch her burn.

Dead men are strewn around the square. The sun lights up mounds of ash where the Baobhan women died, and even these are soon scattered on the wind. The Doctor watches the ash dissipate. A lone voice breaks the silence, the only man left in Thornton Rising. Nate runs towards him, asking for help for Charity. He says that she danced with him to save his life so he saved her. She is cowering in the shadows of her home. The Doctor says he will help but he needs to find something on the moors.

Hours pass and then there are a series of harsh knocks on Nate’s door. He finds himself confronted by the Doctor. Behind him stands the TARDIS. The Doctor enters. Charity is whimpering, cowering from him. Her sapphire eyes burn fiercely. She tells the Doctor that she did her best to save the Doctor. She looks around her house and wonders what will become of her. The Doctor offers to take her and Nate to a planet where the sun will never rise. She thinks of her life of yearning for something more and chokes on the decision before her. She sobs that she cannot ruin Nate’s life. The Doctor comforts her and offers her the choice again.

He leads her to the TARDIS. She is speechless when she looks into the interior. She can feel the energy crackling in the chamber. She asks that he doesn’t drop her on the first world they come to. The Doctor smiles and says that they can travel to a thousand different worlds if she likes until she finds one that she likes. He tells her that she can say goodbye but she reminds him that her perfect world is Earth, with Nate, and that if he reopens the door she will never leave. Smiling through her tears she tells him to set the TARDIS in motion.