The first story arc for the Thirteenth Doctor in 2021 needs a ‘Previously on Doctor Who’ introduction more than many. It follows on from a multi-Doctor story with 13, 10, Weeping Angels and Autons beggaring about with time and paradoxes, from which if everyone escapes unscathed, it’s something of a Time Lord miracle.

As Alternating Current begins, there’s quite the sense of ‘Out of the frying man, into the deeply wrong parallel Earth caused more or less by what the two Doctors did to stitch up the last temporal crisis.’

So it’s business as usual, with a 2021 twist.

There’s lots to tell you, and every single atom of it will be spoilerific to somebody, which means picking a pathway through the story and giving you something to whet your appetite is tricky.

First, let’s say that paradoxes…are…weird. When the Doctor and her fam arrive on Earth, it’s clear within a page that something’s gone badly wrong, but that, miraculously, the Doctor and the Tardis haven’t turned up in the nick of time to help overthrow the forces of oppression.

No, this time, they’ve been here for years, and have got their feet well and truly under the Earth’s table. That means a very different approach to the problem – half Rosa-style wait and see, half-Genesis of the Daleks-style stop-it-before-it-starts action.

Without giving too much away, the villains here are familiar to fans from the 70s and 80s (or indeed, fans with a DVD collection), and you sort of hope to understand a little more about their methods, mindset and culture, but beyond a bit of stomping about with slave-gangs, that doesn’t really happen here.

In its defence, there is rather a lot to cram into Jody Houser’s story. Because the nominal villains from Classic Who might not in fact be the showrunners of this invaded Earth. There may just be rather more going on with a force from New Who – in fact from the 13^th Doctor’s own history with her fam.

If you want to be particularly mean, it’s true that there are holes in the plotting. There is a justification given why the New Who force would want to use the Classic Who villain as boots on the ground for a conquest of Earth – it’s just that it makes more sense as a way of giving the story some juicy visuals than it does as an actual invasion strategy.

Certainly, when the Classic Who villain appears, there’s a cheer that goes up in your brain – partly because of who those villains are, and partly because of how they’re drawn and coloured by Roberta Ingranata and Enrica Eren Angiolini respectively. You nod your head, because they look both like you remember them on-screen, but also, in occasional panels, like something’s been added to their legacy, and added well.

When the New Who force arrives, it’s a little more difficult to raise the instinctive cheer, because what Houser gives us here is the flip-side of a story we’ve already seen. A story where the Doctor and her fam thwarted some evil plans. Given the paradox which resulted when the 13^th and the 10^th Doctors met each other in previous issues, the Earth on which we stand in Alternating Current is an Earth in which 13 and her crew were not there to avert a plot, and so it went on without them, changing the world of our past, to produce a 21^st century very different from our own. An Earth under invasion, with humans as slaves.

It’s an Earth with more than one resistance cell on it, and there are surprises in store for you in each of them. How much you enjoy those elements depends on how much nostalgia you have in you for a previous era of Doctor Who. There’s also some classic Doctor Who technobabble about how some things can be happening to the people affected by them, which you will probably need to wind a string around your head to keep track of.

But overall, Jody Houser pulls off a kind of Back To The Future II version of a story we thought we knew, tweaking details of a past adventure through the mechanism of a paradox to give us something new and emotionally satisfying. In particular, her take on an alternative to a character seen on-screen is involving, with a strong emotional arc of sacrifice, forced by believable circumstance as well as narrative need.

By the time Alternating Current ends, you’ve been at least a little through the wringer, more with this new character arc than any of the nostalgia particularly. Here, the nostalgic story-strand with old friends popping up in new ways is more a downbeat pulse, to keep the piece moving, while the new character evokes both a sympathy and a sense of loss, a way things could have been, but now will never be. Nevertheless, they work pretty well together, especially as the story-strands are passed back and forth like a game of dialogue-catch. And Houser gives us quite the jolt in the last panel of the story, a “Hello again” cliff-hanger that promises much and pulls you forward to your comic-store of choice to see how the heck that turns out.

In terms of the artwork, there’s plenty about Alternating Current that is lush. Thirteen’s Tardis has never glowed quite this brightly, the Classic Who villains are all sorts of right, and the artwork of the new character grows on you fast, giving a version of an on-screen species that can be viewed with sympathy. If there’s anywhere to quibble with the artwork, it’s more in the character-capture than anything background-related. The backgrounds are more or less universally gorgeous – even when they’re gorgeously dingy, blue, cold and hopeless, as some prison shots here are. The shots of the Tardis in the vortex are joy in two dimensions. Some of the historical flashback sequence is beautiful too, including the elements that add to the legacy of the Classic Who villain. All that feels right.

But there are some characters in Doctor Who that are notoriously difficult to get right in a strip-style, and there’s an element of that here. Peter Davison – famously a Doctor with ‘a pleasant, open face’ used to occasionally complain that when he appeared drawn on Doctor Who product, it was ‘someone else wearing my costume.’ That’s an issue that raises its head in comic-books from time to time, even in capturing Jodie Whittaker – you can get there with the facial delineation, and there are certainly some looks she’d pull in the on-screen version, but occasionally, you need to let the dialogue and the rainbow-shirt carry you through and over a hump of ‘Who’s that?’ It’s much more noticeable with one other character though, who rarely if ever looks like themselves in comic-books, and frequently doesn’t reliably look like they did a few panels back. That shouldn’t really be a problem, but as they carry around half the storytelling duty here, it does begin to grate slightly.

Overall, Alternating Current sets out to do a few important things, and ends up doing most of them. Some more interaction with the Classic Who villain could have been useful, if only to explain how they let themselves be used by another force. As it stands, they’re here because they’re here, and that’s about as much as can be said. They look brilliant, but do very little in terms of the story.

But in telling a tale of a paradox and its impacts on the world when not one but two Doctors weren’t here to prevent some things from happening, you end up with a story that has elements of Time Crash and elements of Turn Left, but a Turn Left if the Doctor had suddenly turned up halfway through and tried to put things right. It’s an elegant storytelling conceit, and Houser, Ingranata and Angiolini spin the story for us effectively, always keeping the character-beats and the voices right, always giving us something interesting to look at, and letting us close the book with a satisfied smile. Tony Fyler