The Eaters of Light (TV story)

 was the tenth episode of series 10 of Doctor Who. It was written by Rona Munro, directed by Charles Palmer and featured Peter Capaldi as the Twelfth Doctor, Pearl Mackie as Bill Potts and Matt Lucas as Nardole.

Munro returned to writing for the programme after nearly 28 years since her last television script, Survival — the end of the "Classic" era.

The episode answered the question about what happened to the Ninth Legion of the Roman army, and featured the return of, revealing the Doctor never put her back in the Vault after being let out before. The episode also shows the Doctor and Missy considering mending their broken friendship.

This episode marks the first Bill becomes aware of the TARDIS translation circuits. However, this story also makes note that the TARDIS also does "lip-synch" when it translates a different language into a time traveler's native language.

Synopsis
What happened to the legendary Ninth Legion of the Roman army? Bill and the Doctor both have ideas of what happened, but who is right? What is that strange creature lurking in the dark? And why are people suddenly disappearing?

Plot
In the present day, in the Devil's Cairn, Scotland, a little girl named Judy goes to a slope against her brother's warnings saying that she wants to hear the music. He tells her that there are ghosts there and that if she stays there, they will eat her. As they go back to the village, Judy turns and goes back to the hill, while a crow alights on a stone, saying "Doc-tor! Doc-tor! Doc-tor!, Doc-tor!", as a carving of the TARDIS is seen on a rock.

The TARDIS materialises in the moor, Aberdeen, Scotland, 2nd Century AD. Nardole exits the TARDIS in his pajamas and dressing gown, asking why they are not guarding the Vault THIS time; the Doctor laughs that Nardole didn't have a problem when it was Victorian Mars last time. The Doctor says that Bill thinks that she knows more about Romans than him; so he's come tor prove her wrong about what happened to the lost Ninth Roman Legion. Bill is confused as the Romans should still be there, prompting the Doctor to point out that they'd still be seeing 5000 Roman soldiers walking away past the hills.

However, Bill reminds the Doctor that Romans follow the river, as it ensured they had water to drink on their journeys. The Doctor laughs, saying she has much to learn about Roman Brittan; he's lived there, governing, farming and juggling. He was even a vestal virgin Second Class. Bill stops him, betting that she can find the Ninth Legion by following the river; the Doctor agrees to the wager, deciding to look for the Ninth Legion's last battlefield. Bill walks off, promising to bring back a Roman soldier. An astonished Nardole questions the Doctor about being a second class vestal virgin, to which he says its a long story.

Bill explores the forest near the river, unaware some kind of creature is watching her. Seeing smoke near by and with voice coming from the same direction, Bill cracks a smile and walks over. However, its not a Roman, its a Picktish girl burning belongings of her dead relatives, stating the she honors each one. Bill unintentionally snaps a twig underfoot, alerting the girl to her presence; before Bill has a chance to say anything, the girl picks up a sword and roars a battle cry. Bill runs quickly, managing to outrun the girl thanks to her tripping a lot. A good distance away, Bill catches her breath and looks around; assuming its safe, she accidentally falls into a hole. Now trapped in an underground pit, she is met with a sword, which is owned by a Roman soldier.

Elsewhere, the Doctor tells Nardole to look for some kind of obvious sign of the Romans presence - burning huts, slaughters locals, sweetie wrappers... As they walk Nardole hears a crow say "Dark" repeatedly; the Doctor tells him all crows can talk, but are in a mass sulk in the future because humans don't have intelligent conversations with them anymore. He explains they are hurrying because the crow is warning them of danger; they don't have a lot of daylight left. They arrive at a stone camp, which the Doctor explains was built under the ground but close to the sky out of a belief that they are doors between worlds. Calling it an Iron Age church, the Doctor explains that a human settlement must be near by; there's no point in building a place of religious importance otherwise. Nardole complains its damp, to which the Doctor states "its Scotland. Its supposed to be damp."

Back in the pit, Bill is pacing around. She says to herself that she wished she spoke Latin so they could converse. The Roman tells her that she IS speaking Latin; Bill is surprised to hear English coming from the Roman; however, the Roman states he hears both of them speaking Latin. Bill quickly postulates that she can hear English from someone who doesn't speak her native language due to either the Doctor or the TARDIS. When the confused Roman questions her rambling, Bill notes that the "auto-translate" even does lip-synch for the translations. Bill introduces herself and asks the Roman if he's from the Ninth Legion. Confirming it, the Roman asks Bill if she saw what befell rest of his Legion.

Elsewhere, the Doctor and Nardole find a Roman corpse. However, it is discolored blue and mushy. The Doctor says the victim's bones disintegrated from a complete lack of sunlight; "death by Scotland" Nardole jokes about the overcast weather. However, the Doctor tells him that this would take DECADES of lack of exposure to the sun; this happened a short while ago. The most logical solution is that an alien of some kind has arrived on Earth and is either harvesting or eating solar energy. The Doctor questions where the rest of the Ninth Legion could be and walks off to search. Nardole complains about wanting to go back to bed. They come across a battlefield littered with similar corpses and fires still burning; its the Ninth Legion. The Doctor notes that this massacre didn't happen too long ago, meaning whatever killed the Ninth Legion is still nearby; they need to find Bill before whatever did this gets to her first. However, right as they attempt to leave Picts ambush them and take them hostage.

Night.

Bill and the Roman climb out of the pit. Hearing something nearby, the Roman tells her its what slaughtered the Ninth. He reveals a handful of Romans have survived. As they walk off, the Roman reveals they only survived because they ran. The creature nears. The Roman tells her they're underground near the river and to look for a carving. The creature grabs the Roman with tentacles from its mouth and feeds off the sunlight in his body, killing him. It chases after Bill, but she manages to find the cave the Romans are hiding in. AGAIN, she is met by a sword. However, one of the creatures' tentacles lashes her shoulder. The Romans let her in and block the entrance. In a candlelit area, they rest; Bill reveals the death of their comrade, Simon. Bill notices the creature left black slime on her and passes out.

Elsewhere, the Doctor and Nardole are being held captive in a hut and at spear-point. The Doctor asks how long they intend to keep them there, hoping for a chair. A boy tells them to stay silent and be still until his sister Kar, Keeper of the Gate, arrives. "Well, let's hope she's the brains of the family." the Doctor states; they're basically the Little Pigs living in a house of sticks and a Big Bad Wolf of a monster is out there, ready to blow it down and eat them. Nardole takes put a bag of un-popped popcorn, asking if anyone would like any; at least he's trying integrate himself better than the Doctor. The Doctor tells him to knock it off as he's against charm, being told to be silent again. The Doctor shushes everyone and asks if they just heard something; "that was the sound of my patience shattering into a billion little pieces." He pushes the leader back with authority, demanding to know where his friend is and what destroyed the Roman army. Kar, the girl who attacked Bill, walks in and claims credit; she apologizes to her brother for taking too long, as she was getting the Gatekeeper weapons. The Doctor says its an impressive trick if she did kill the Ninth Legion, but then wonders where the adults are. Kar says it was a great battle (meaning they're all dead), but they beat the Romans. The Doctor laughs that a child beat them, asking if she threw her toys at them.

Kar calls them Romans, telling them to be silent; the Doctor and Nardole state that they are not Romans. She tells them the "truth" about Romans; they'll steal from the rich and enslave the poor. They make an empire out of slaughter and plundering, calling it peace. Taking this in, the Doctor adds a positive about Romans - they have indoor toilets. Noting that that killing 5000 Romans would be impossible for Kar, the Doctor remembers she's called a gatekeeper and she has gateway weapons. The question is what kind of gate is that and what's on the other side. The Doctor grabs Nardole's popcorn bag and tosses into the fire, asking them to "jump out of their skins" so he and Nardole can escape in the confusion. Suddenly, the popcorn pops, scaring the Picts. The Doctor and Nardole flee.

Back at the cairn, Nardole asks if they're looking for Bill. The Doctor tells him that they are looking for maximum danger in the immediate area and walking into it. If she's there, they'll save her; if she's not, she's safe. Nardole rests outside the cairn, while the Doctor goes in and ponders about the gate Kar mentioned; very possibly there's an actual gateway in there. The Pics grab Nardole, telling him that the gate is opening and that the Doctor won't be back. The sun rises; the light enters the cairn and opens a hidden passage with a blue void.

The Doctor enters the portal and sees several hostile creatures floating in the void; one roars at him, startling the Doctor backwards, out of the gateway. Back in the normal world, the Doctor hears Nardole telling a story from outside of the cairn. He exits outside to find Nardole in Pic garb, telling stories about his past travels to the assembled group. Seeing the Doctor, Nardole is surprised as the Picts told him that he'd never come back; for him it's been two days, while for the Doctor its been seconds. The Doctor realizes time goes slower in the void. He asks Nardole if he found Bill; they looked, but got no result. The Doctor is still hopeful, telling Nardole that she just wasn't where they looked.

In the cave, Bill is awoken by a Roman named Lucius. He tells her to move into a beam of sunlight coming from a hole in the cave to burn the black slime off. He gives her some food to regain her strength. Bill says she has to leave, despite protests that the beast is still out there.

While searching for Bill with Nardole, the Doctor runs into Kar, who is surprised to see him back from the cairn. He asks if she knew what was in the gate; its a portal between dimensions. Seeing she has no clue, the Doctor dismisses her as nothing more than bluster. Kar reveals its called the eater of light and that each generation a warrior would hold it off. However, it got out and killed the Ninth Legion. Kar says it will die soon because its weak. The Doctor tells her that other Eaters will come out of the gateway and there's no way she can hold them back, sarcastically asking if she's holding her weapon the right-way up. Kar refuses the Doctor's help, as a scream rings through the air.

In the cave, Bill notices Lucius fancies her. She tells him that she's only interested in girls; he compares her to his comrade Vitus, who only likes men. Vitus scoffs he likes men better-looking than Lucius. Lucius accepts Bill for knowing what she likes; Bill then asks about Lucius. Lucius states that for the rest of them, bisexuality is normal for Romans. Bill laughs at how modern Romans were about sexuality. Lucius offers to be a friend instead, which Bill accepts. They are startled by the creature, which has found their air hole.

Outside, a new corpse is found, this time its a Pict girl. The Doctor states that the creature is feeding off the sunlight, hence why it keeps getting darker; there's very little time left to stop it. Kar blames herself; the Doctor realizes the beast was released as a desperate effort to kill the Romans. Kar thought it could be fatally wounded as it slaughtered the Ninth. However, all this did was anger the beast; the Doctor tells Kar that she just doomed the world to protect her home.

Back in the cave, Bill has told them of the Doctor and how he can help. However they are skeptical as a beast of darkness and barbarians await them. She tells them that being scared doesn't make them cowards; it makes them human. Bill tells them that being scared isn't a plan; she can at least promise them that they won't die in the cave. Lucius rallies his men to follow Bill's plan to seek the Doctor for help against the beast. Seeing the other Romans calling Lucius granddad, she questions why; it's because he's the oldest at 18. Bill silently laughs about this to herself.

Back to the Doctor, he's devised a plan. They need to drive the eater of light back into the portal. However, he is confused by why sunlight opens it. Its because the ancestors who originally built the cairn couldn't properly shut the portal; so they sent a warrior in once a generation to keep the beast from getting out. Nardole compares it to venting an oil gush. Seeing Kar sulk, the Doctor tells her to save mourning the dead for old age; the more time she spends wallowing in that thought, the more people are going to die. He inquires about the mirrors on sticks Kar has, learning it poisons light the beat eats. The Doctor tells them they need to lure the best to the gate before sunrise, when its weak.

Back to Bill, she and the Romans move through a passage in the cave; they spent the last few days exploring to find ways to sneak past the beast. They come across a ladder, which Lucius says leads up to the village of the barbarians; voices and light come from above a trapdoor. Lucius asks Bill if she's sure the Doctor is with the barbarians; "basically, he always ends up being boss of the locals" Bill states. Cornelius attempt a walking to the ladder, but is eaten by the beast. Bill and the others rush up the ladder as the Eater is preoccupied.

They pop through into the room the Doctor and Nardole are in; Bill helps block the trapdoor. After greeting the Doctor, Bill smugly says she brought him the Ninth Legion. She then notices Nardole in a 2nd Century robe and face paint, asking what happened; Nardole states that he's blending in, mimicking a Scottish accent. The Romans take a defensive formation against the Picts, who want revenge. The Doctor and Bill tell them that they don't have time for this. Kar tells Lucius that her people lived in peace until the Romans came, laying waste to everything and everyone they loved. The Doctor tells her the Romans understand her, but are confused as to why. Bill says its because of the Doctor's presence; it allows anyone near him to hear their native language from other people.

Both the Roman and Picts realize that their respective enemies are just children. Bill realizes that the Doctor can understand everyone in the universe and they all sound like children to him; the Doctor says there are exceptions. Nardole thanks him, to which the Doctor says he was talking about Bill. Recapping the deaths that each side has caused the other, the Doctor tells the group that they can continue to childishly slaughtered each other until there's no-one left or "YOU GROW THE HELL UP!" The Eaters are the real threat; if they break through, they will eat the suns and stars, dooming N-Space. Both groups agree to work together. The plan is to lure the Eater with music to the cairn, where they will force it back into the portal.

At the cairn, the Doctor sets up the trap, explaining to Bill that a Pict fighting one off for a few minutes buys 60-70 years of peace and then they get replaced; however, human lives get used up too quickly, leaving the possibility of eventual failure. He tells Bill he has a better idea, which she says is the part he never tells her; the Doctor says its usually because he gets interrupted. Bagpipe music plays, annoying Nardole, who finds it worse than jazz. Outside, the beast arrives and runs inside; using the mirrors, light from torches is turned poisonous to the beast, weakening it. The Romans and Picts stab the best to keep it still until sunrise.

The portal opens and the beast is forced inside. The Doctor revealed he plans to fight the beasts for eternity has his ability to regenerate and slow aging would allow him to indefinitely keep the universe safe. However, he is knocked down by Nardole, who whacks him on the head with one of the mirrors. Kar states that she is the gatekeeper and that it's her responsibility. The Doctor states she'll be a hero for a minute and then the world is doomed. However, Lucius states that the Ninth Legion will fight as well. His men follow Kar and the bagpipe player into the portal. Lucius gives Bill a smile as he follows as well. Suddenly, the cairn begins shaking. The Doctor says too many people going through the portal destabilized it. Everyone runs out as the cairn as it collapses in on itself; the portal shut forever.

Nardole tells the Doctor to let go of any grudge he might have for incapacitating him as he knows 10% of his darkest secrets; he's also the only one who knows where the tea cakes are in the TARDIS. Kar's brother tells a crow to spread her name it flies off, cawing. Nardole laughs that the Doctor was wrong; crows is in the future aren't in a huff, they're remembering Kar. The TARDIS trio walk off, with Bill reminding the Doctor he can't take on every fight as he has to guard the vault. The Doctor admits he was wrong about the Ninth Legion; they were never really missing.

Entering the TARDIS, Nardole suggests they finally go home. They last thing they need is Missy getting any ideas if they're gone too long. He then becomes shocked to see Missy casually reading a book in the Doctor's recliner. Missy tells the group that she was starting to worry about them since its been days. Seeing how shocked Bill and Nardole are to see her, Missy asks the Doctor if she should have remained below deck; however, the Doctor tells her it's fine. Nardole demands to know why Missy is in the TARDIS. The Doctor reveals that he had Missy do some maintenance on the TARDIS engines for him; they were in pretty bad shape.

Missy calms Nardole by explaining she's bio-locked out of the controls, preventing her from stealing the TARDIS (like last time); she's just as trapped in the TARDIS as much as she was in the Vault. Missy reveals she's been watching their adventure on the monitors. Recapping the end, she asks if its up to the Doctor's bleeding heart standards. The Doctor says there's always music. Missy asks Bill and Nardole for help hiding his guitar. He tells Missy that she might understand the universe, but she can't hear its music; however, he's got plenty of time to teach her.

After Bill and Nardole leave the TARDIS, Missy listens to the bagpipe music, deep in thought. She finds herself crying and turns to find the Doctor. Missy is confused as she doesn't understand why she's crying. The Doctor suggests that she's trying to impress him; Missy agrees that it must be part of some kind of scheme. However, the Doctor adds the other option is much worse; Missy is feeling sorrow for the people who gave their lives, meaning its time for them to rebuild their friendship. Missy is happy to hear it, but the Doctor remain a unsure if they're at the right stage of her rehabilitation.

Cast

 * The Doctor - Peter Capaldi
 * Bill - Pearl Mackie
 * Nardole - Matt Lucas
 * - Michelle Gomez
 * Kar - Rebecca Benson
 * Ban - Daniel Kerr
 * Lucius - Brian Vernel
 * Simon - Rohan Nedd
 * Thracius - Ben Hunter
 * Vitus - Sam Adewunmi
 * Cornelius - Bill Matthews
 * Marcus - Aaron Phagura
 * Judy - Jocelyn Brassington
 * Brother - Lewis McGowan

Crew
to be added

Culture

 * An image of the TARDIS has been engraved into a Pictish stone.
 * The Doctor says that Picts are early Celts.
 * The Doctor call the cairns "Iron Age churches".
 * The Doctor says that this adventure is "not [my] first rodeo".
 * In Roman culture, bisexuality is "ordinary", and only liking one sex is taken as a surprise. Lucius accepts Bill for only liking women, and relates her to Vitus, who only likes men.
 * The Doctor suggests that the Picts name a cow after him, on their return to safe farming.

People

 * Kar and Ban are Picts.
 * The Doctor has lived in Roman Britain, governed, farmed, juggled. He was once a second-class Vestal Virgin.
 * Kar is the Keeper of the Gate/Gatekeeper.
 * The Doctor tells Bill to hit the TARDIS console with a spanner to get it to take her home.

Locations

 * The Doctor, Bill and Nardole visit the Devil's Cairn in Aberdeen, Scotland 2nd century AD.
 * The Doctor mentions their recent trip to Mars.
 * Nardole tells the Picts about one of his adventures involving the Mary Celeste. He was also going to tell them about the Lusitania.

Languages

 * Bill thinks the Roman soldier Simon is speaking English.
 * Simon thinks Bill is talking Latin.
 * The Picts and Romans can understand each other, not just Bill, Nardole and the Doctor.

Species

 * Judy's brother believes that the music at Devil's Cairn is due to ghosts.
 * According to the Doctor, all crows can talk, but human beings stopped having intelligent conversations with them, so by the 21st century they're all in a "mass sulk". Nardole corrects him by saying they're remembering.
 * The crow on the Pictish stone with TARDIS engraving says "Doctor" in a garbled voice.
 * Ban tells the crows to bring Kar's name into the skies, hence their signature call.
 * Simon says the other soldiers are hiding at a location with a stone-carving of a fish.
 * The Doctor sees multiple light-eating locusts inside the Gate.
 * Nardole tells the Picts about Enzomodons and says the Enzomodon ambassador had choked.

TARDIS

 * Bill discovers that the TARDIS can translate languages. She discovers that it even does lip sync.
 * Bill finds out that foreign languages translated sounds like children-talk.

Food and beverages

 * Nardole is eating a teacake.
 * The Doctor suggests the Romans could have left "sweetie wrappers" as a sign of them being there.
 * Nardole says he isn't Italian, but makes "a mean spag bol".
 * Nardole brings bags of popcorn, one of which the Doctor uses as a distraction.
 * Lucius gives Bill a flatbread to eat.
 * The Doctor calls Kar's light-poisoner a lollipop.
 * Nardole says he knows 10% of the Doctor's secrets, and he's the only one in the TARDIS who knows where the teacakes are.

Technology

 * The Doctor asks the Picts for the Wi-Fi password.
 * Nardole says the cairn works like an oil gush.
 * Missy mentions the Doctor's electric guitar.

Music

 * Scottish music can be heard at the hill at Devil's Cairn.
 * Nardole says that Scottish music is worse than jazz.

Story notes
to be added

Ratings

 * 2.89m (UK overnight figures)
 * 4.73m (UK final)

Despite the ratings being the lowest an episode of the revived series has ever acquired, it still received over 30% of the share of the audience, behind only The Pilot for Series 10.

Filming locations

 * The scenes in "Scotland" were filmed on the Brecon Beacons, in Wales. The cave used for filming was Porth yr Ogof.

Production errors
During the scene in which Kar describes the work of the Romans, a mic boom can be seen at the top of the screen.

Continuity

 * Nardole reminds the Doctor of his oath to guard the Vault. (TV: The Pilot et al.)
 * Bill previously suggested travelling to Aberdeen. (TV: Smile)
 * The Doctor says he once lived as a Roman. (TV: The Romans)
 * Nardole gives a different perspective on the mystery of the Mary Celeste, (TV: The Chase, PROSE: The Mystery of the Marie Celeste, COMIC: A Stitch in Time) having previously had the ship's sign stored near the vault. (TV: The Pilot)
 * The Doctor reminds Bill and Nardole about on Mars. (TV: Empress of Mars)
 * Bill turns someone who likes her down because she's not interested in men. (TV: Knock Knock)
 * Bill figures out the TARDIS has granted her the ability to understand numerous different languages as she was informed she was speaking Latin to a Roman soldier, (TV: Rose, et al.) strikingly resembling Donna Noble's revelation when supposedly speaking Celtic. (TV: The Fires of Pompeii)
 * Bill says that "scared is fine" and "human". The Doctor previously told Rupert Pink that "scared is a superpower". (TV: Listen)
 * The Doctor has met centurions before. (TV: The Romans, The Pandorica Opens)
 * The Doctor says he have been protecting Earth since the beginning. (TV: An Unearthly Child et al.)
 * The Doctor says the TARDIS can easily take Bill home if she just leaves the settings on. (TV: The Parting of the Ways)
 * Missy mentions the Doctor's electric guitar. (TV: The Magician's Apprentice et al.)
 * Missy is again seen crying. (TV: The Lie of the Land)

DVD releases
This episode was released as part of the Series 10 DVD box set on 13 November 2017.

Blu-ray releases
to be added

Digital releases
to be added