The Eaters of Light

Munro previously wrote Survival, the final serial of the original run of Doctor Who, making her the only writer to date to have worked on the classic and revived eras of the show.

The Doctor (Peter Capaldi) takes Bill (Pearl Mackie) and Nardole (Matt Lucas) to second-century Scotland to settle their different theories about what happened to the ninth legion of the Roman army that vanished.

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.

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.

With the portal closed, the remaining Picts honour Kar's memory in monumental stones and by teaching the crows to say her name, which Nardole observes continues into the present day.

Club gave the episode a grade of B+, praising veteran writer Rona Munro on her script, and how she "skilfully mixes the political and the personal", specifically on the usage of the Roman army and the complexity of the characters of the soldiers.

She felt that it was a solid episode with plenty to enjoy in terms of the story, including Nardole's inclusion with the natives, the Doctor's talking about the crows, and Bill and her discovery of the TARDIS' ability to translate.

She commented on the predictability of what would happen when the Doctor declared that he would guard the gate – how the viewers would expect that the supporting cast would take his place instead.

Collura commented on the amusement of the conversation between Bill and Lucius regarding his romantic intentions, and the girl Kar with her pain and history of having lost everything.

[12] Patrick Mulkern from Radio Times gave the episode a perfect score, calling the script "beautifully written".