While I’m not planning to go into a lot of plot details, it’s likely that the random mutterings that follow will reveal some things you might prefer not to know if you haven’t seen the episode yet, so in my usual way, I’ll include this warning:
This episode was written by Rona Munro, making her the first writer from the 20th century run of the show to write in the modern version. And nobody is worried that the story she wrote way back then was Survival, the last one for a very long time. Look, it wasn’t her fault, OK?
Anyway, the Doctor, Bill and Nardole have arrived in second century Scotland. Nardole is distinctly unhappy about this, as the Doctor is supposed to be guarding Missy, who’s back in the Vault after last week’s Martian fun. But, as the Doctor explains, it’s all Bill’s fault, because she insists that she know more about Roman Britain than he does, so there. He’s not convinced, after all, he does have, err, history
Speaking as a former Vestal Virgin, Second Class….
Well, the point of the story is finding out what happened to the Ninth Legion who really, really did disappear. Well, no it isn’t. The point is people coming together and sorting out a trans-dimensional alien wossname. Well, possibly not that either. It does offer some fun when Bill works out that the Tardis handles the little matter of translation, leading to much silliness when a Roman soldier tells her
You just said that in Latin!
Though the best silly bit is when she notes that
it even does lip-sync
Which is as sensible an observation as the one about why if he’s an alien does he name his space-time capsule in English…
But that’s not really what this episode and the last few are really about at all. It’s all really about Missy, who to the surprise of nobody except Bill and Nardole isn’t in the Vault at all, but has in fact been doing some Tardis maintenance. Oh, and crying. Could she really be showing genuine signs of remorse? Could she, in fact, be changing, reforming, even?
Well, we’ll find out soon. And things look like getting very confusing indeed, which can only be a good thing…
 There are a lot of centuries in this post for some reason to do with time