‘Now we know what our task is. Keep history in order. No changing it.’ Modern Doctor Who historicals have largely treated the past like it’s the present in funny clothes. Rosa goes back to an older concept, the Lucarotti historical where the past is – literally – a foreign country, as strange and horrifying as an alien planet and where none of our modern assumptions can be taken for granted. That it’s the relatively recent past of American segregation tends to make this even more disturbing than something like The Aztecs.

Malorie Blackman very effectively recaps the systemic racism of Montgomery, Alabama. A prologue in 1943 shows Rosa Parks has been facing it her whole life, and that the events of 1955 were a long time coming. That our window into this is Ryan, a character we’ve come to like, makes the attitudes of the Alabamans seem even more heinous. He’s slapped, called names, forced to sit at the back of the bus, and refused service in a restaurant. The show has skirted with these prejudices before, notably in Thin Ice, but Rosa makes it the whole story, and spends some time on the psychological consequences of Ryan’s experience, while also offering up something positive as he gets to meet Martin Luther King and assure Rosa that things will improve thanks to her actions, even if they fall far short of perfection.

I think the script gets it right by having the villain be a petty man – events since 2018 have shown petty men unleashed remain a threat to US democracy and social progress. I also think it gets the climax right – the villain is banished back into the distant past, and having dispatched him, it just falls to the TARDIS crew to make up the numbers on the bus and the audience for Rosa’s crucial act of defiance. What particularly sells this is Graham’s evident distress at even passively becoming part of events. This is not the triumph of restoring the course of history, but the grim horror at making a sacrifice for the sake of the future.

Which brings me to the coda, which seems suddenly ill judged. I think Whittaker misplays the “what comes next” summary with too much enthusiasm, when what was needed was something closer to the matter-of-fact voiceover at the end of The Family of Blood (elsewhere she gets some much better moments, like her reaction to Graham putting his hand on her shoulder when they’re quizzed by a cop). It doesn’t help that the earwax time rotor bobs up and down behind her throughout. And then, having Rosa’s lasting memorial turn out to be a lump of space rock is bathetic – at least have them in orbit of a sparkling colony planet or a fabulous spaceship.

Mostly, though, this is a story that’s well told and well worth telling. It manages to incorporate the crowded TARDIS crew well. It’s like Hustle, with a key role for each: Yaz is the fixer, putting her police skills to use. Graham is the roper, ingratiating himself with the locals. Ryan is the inside man doing the legwork. And the Doctor is the brains, flitting around the edges, keeping Krasko at bay while her gang does its work. Yaz is already showing she’s got a crush on another crewmember – and it’s not the Doctor. She’s clearly into Ryan, as they bond over some of the prejudice they still face in the 21^st Century. With a directness that’s quite different from Moffat’s storytelling, this is the new, linear approach done very well.

Next Time: Arachnids in the UK