A segregated cinema in Miami, 1952, where people have been vanishing into the screen and a cartoon mascot has become a living god of light. “Lux” is the most visually inventive episode this era has made and one of the strangest things the show has broadcast in years, and I came out of it genuinely unsure what I thought. Parts of it are terrific. One sequence near the end is either the boldest thing Davies has done or a serious misjudgement, and I keep changing my mind about which.
Alan Cumming voices Mr Ring-a-Ding, and the design is superb: a black-and-white rubber-hose cartoon that moves like a 1930s animation and behaves like something very old and very hungry. A cinema is already a place where people sit in the dark and watch light on a wall, so a creature made of light living in a projector needs almost no explaining. The episode trusts that and gets straight on with it. He’s strongest when the projector runs and weakest in darkness, and there’s a good sequence of people trying to decide whether to keep the film rolling or cut the power.
The animation sequence is a triumph
The standout is the stretch where the Doctor and Belinda are pulled into the film and drawn as cartoons themselves. It’s fully animated in period style, it’s funny, and it’s frightening in a way live action couldn’t manage, because the rules of a cartoon body aren’t the rules of a real one. That’s the best use this era has made of its budget. It isn’t spectacle for its own sake, it’s a sequence that could only exist in this story, and the gag about the Doctor’s cartoon physics wearing off at exactly the wrong moment justifies the whole idea.
Cumming is excellent throughout. Ring-a-Ding is playful, then petulant, then genuinely enormous when he drops the voice, and the moment he explains that he’s been trapped in celluloid for decades and simply wants to be seen has real sadness in it. He’s another Pantheon god, and by some distance the best realised of them. The horror beats are strong too, with the vanished people rendered as flickering silhouettes trapped in the film stock. What happens when the light goes out is properly unsettling.

The 1952 setting has teeth
The cinema is segregated, and the episode doesn’t treat that as background. The Doctor’s reaction to being in Florida in 1952 is played with a tightness Gatwa handles very well. What I liked is that it’s concrete instead of declared, so nobody makes a speech. There’s a moment where the Doctor is stopped by a policeman and has to decide, visibly, how to survive the next thirty seconds, and Gatwa plays the calculation without a word. That’s the difference between a theme and a lecture, and it’s what made The Idiot’s Lantern work: put the horror in one household on one street and let people notice it themselves.
Reginald, who runs the cinema, is the best of the supporting cast, and Linus Roache plays him with a bone-deep weariness. His grief, and the bargain he’s made with the thing in the projector, gives the episode its one genuinely warm thread. Belinda is excellent again as well, and the double act is settling into something distinctive. She keeps asking the questions a nurse would ask: is anyone hurt, where are the bodies, what happens to the people in the film when it burns. Two episodes in, she’s the most immediately useful companion since Donna.
The bit I can’t decide about
Then the episode steps outside itself. The Doctor and Belinda are dropped into a living room where three fans are watching an episode of Doctor Who, discussing its flaws, and the Doctor realises he’s a fiction. I can see exactly what it’s for, since the whole episode is about people trapped inside films and putting the Doctor inside one completes the pattern. It’s also a decent joke at the expense of a particular kind of fan, delivered with more affection than mockery. It stops the story dead, though, and the fans are simply left behind with no consequence.
My real problem with it isn’t that it’s clever-clever. It’s the third time in two series that this show has reached for a get-out that sits outside its own rules: a god who can do anything, a memory that makes it snow indoors, and now a Doctor who might be fictional. Each one on its own is a fun swing, and together they add up to a programme that keeps telling me its own stakes are negotiable. I can see the case for the detour as a warm nod to the fans, and it’s easier to forgive in an episode this ambitious. An hour that turns into a cartoon for ten minutes and takes segregation seriously is at least trying something, and my reservations are about where the show is heading more than about effort.
Rating: 3/5. It was ok, and I admire a lot of it. The animation sequence is the best thing this era has produced, Alan Cumming is superb, and the 1952 material is handled with real care and no sermonising. It loses ground for a fourth-wall detour that halts the episode. The resolution, once again, involves the Doctor talking a god into leaving.
