This is a post-UK broadcast review of Doctor Who: The Eaters of Light. River Song always warned the Doctor against spoilers, so be sure to watch the episode first. Doctor Who, season 10, airs on Saturdays at 6:45pm UK time on BBC One, and 9pm EDT on BBC America.

The Eaters of Light is one of those Doctor Who episodes that could easily serve as a gentle intro to the Time Lord's universe. And it’s probably up there with this season's Thin Ice in terms of pure, there-be-monsters entertainment for the kids.

Fire breathing dragons are the stuff of Welsh legend, so I guess it follows that light eating locusts—which look nothing like locusts—might be found in Scotland. Better still, the wee beastie that's heavy on its hoof comes equipped with thin, glassy blue tentacles that could be the altnet saviour that some of the Scottish islands stuck in the broadband slow lane need.

But this episode is set yonks ago, so maybe it's a little premature to search for a signal. It doesn't stop the Doctor (Peter Capaldi) from dad-joking about a Wi-Fi code, though.

So yes, a good ep for newbies to the Doctor Who world. There's a portal that has trapped a hungry beast between dimensions; the Doctor jigs his way through problem-solving while reminding Nardole (Matt Lucas) and the audience that he's an old hand at this kind of thing ("trust me, this is not my first rodeo"); and a classic Who story device features: sidekick Bill (Pearl Mackie) is separated from her time-travelling pals for much of the episode—leaving her to untangle yet more of the Time Lord's powers, such as the telepathic link from the TARDIS that auto translates any language to English.

In another nod to the original run of Doctor Who, this week's scribe is Rona Munro. She penned the three-parter Survival back in 1989, when Ace (Sophie Aldred) and Sylvester McCoy's seventh Doctor encountered the Master (Anthony Ainley).

And there are parallels here: Missy (Michelle Gomez) is once again on board the TARDIS. Despite Nardole and Bill's protests, the Doctor says she's been helping him out with a spot of maintenance to the police box.

A teary-eyed Missy is bio-locked out of playing with the controls. But it's difficult to work out if she's now in full-on scamming mode. The Doctor hopes they can be friends (we've been here before, of course). "That's the trouble with hope, it's hard to resist," he says.

The Roman legion-themed episode, set in a damp and ancient Aberdeenshire, works OK as a standalone story. But once again, it does also feel well-worn and as snug as Nardole's retro dressing gown (which is a sweet homage to Douglas Adams' The Hitchhiker's Guide To The Galaxy, surely?).

Meanwhile, the Doctor is really just a bystander offering some comforting and wise words. The farmers and Roman soldiers team up as gatekeepers of the inter-dimensional temporal rift—which looks a lot like one of those aquarium screensavers everyone had back in the '90s—even as the Doctor tells Bill: "I've been standing by the gates of your world keeping you all safe since you crawled out of the slime. I'm not stopping now." But he's easily convinced, after a gentle knock on the head, to look the other way.

This is just one of the reasons why The Eaters of the Light story arc remains planted firmly in the hillside. It suffers from having to remain simple, allowing space at the end for the inscrutable exchange between the Doctor and Missy.

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Simon Ridgway/BBC

Darkest hour

So what can we expect next? The Doctor seems a bit jammed and inactive. Missy even asked him if he was OK at the end of Empress of Mars. Is this a subtle signpost for the audience? It would seem that Missy and John Simm's Master will go face-to-face on screen. So where does the Doctor fit into all of this? How many renegade Time Lords will the finale bring?

I think I'm finally over the idea that the Doctor, Bill, and Nardole are still trapped in the Monks' simulation world. But could that be one of the Monks who flashed before us in the trailer for next week's episode? Plus: Mondasian Cybermen are incoming and Missy's seemingly on a mission to be good. What could possibly go wrong?

The next episode of Doctor Who, entitled World Enough and Time (season 10, ep 11), will air on Saturday, June 24. As ever, check in for Ars’ review straight after broadcast.