The Eaters of Light (TV story)

 was the tenth episode of the tenth series of Doctor Who produced by BBC Wales.

It was written by Rona Munro, who 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.

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? And what is that strange creature lurking in the dark? Why do people suddenly disappear?

Plot
The Twelfth Doctor and Bill disagreeing about the fate of the Ninth Legion of the Imperial Roman army, travel in the TARDIS along with Nardole to the 2nd century in Scotland to prove the other wrong. Bill goes her own way to find the Legion, while the Doctor and Nardole look for their dead bodies.

Bill encounters some of the Legion's soldiers hiding underground, the TARDIS' translation circuits helping her communicate with them. The soldiers are hiding from a "Light Eating Locust" that seems drawn to any light source, killing those in its path. Meanwhile, the Doctor and Nardole discover the boneless corpses of the remaining Legion. They later come across a Pict tribe guarding a cairn and waiting for Kar, their leader and the "Guardian of the Gate". The Doctor impatiently enters the cairn, passing into an interdimensional portal full of creatures feeding off a light source. He comes out seconds later, but finds that more than two days have actually passed. Kar explains that once a generation, a warrior of their tribe goes through the cairn to defeat an "Eater of Light", but with the invading Roman army, she allowed one to escape to fight them. The Doctor warns her that unless they can get the creature back into the portal and close it, more of its kind will escape and consume the sun and all the stars in the universe.

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.
 * Bill has read the book The Eagle of the Ninth, and loved it. She claims she knows more about the Romans than the Doctor.
 * 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
to be added

Continuity

 * Nardole reminds the Doctor of his oath to guard the Vault. (TV: The Pilot et al.)
 * 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
to be added

Blu-ray releases
to be added

Digital releases
to be added