‘I live in the world you leave behind.’ Catherine Tregenna, writer of some of the most striking episodes of Torchwood, arrives in the parent show with a script that similarly prioritises character relationships over action. The 21^st Century series has often raised the idea of the Doctor’s long life, and how living like a human being, day after day, is ‘the one adventure I can never have.’ This episode engages directly with it, of Ashildr’s life on the slow path, eight centuries of loss and heartbreak waiting for the man who did this to her to pop back in. She is another in a long line of girls (and boys) who waited, but of all of them she’s had to wait the longest and suffer the most.

The result is a beautiful character piece. The first 20 minutes are practically a two-hander, and Maisie Williams rises to the occasion with a more engaging and interesting performance than the Arya-lite act she was asked to do in the previous episode. However, the best role is saved for Capaldi. When he’s faced with a prickly, dissociated immortal he has to become her Clara, coaxing her back to reconnect with the feelings she’s buried for so long: ‘You think you don’t care, then you fall off the wagon.’ The Doctor gets to be silly, funny, sad, heroic (racing on horseback to save the life of a man he barely knows, and the conscience of a woman he wronged) and kind. Capaldi nails it. I think it’s easily his best performance in the role to date, and for me this was the episode that justified his casting and made up for the egregious characterisation of parts of Series Eight.

True, the plot itself is thin with some ropey moments (‘Purple, the colour of death!’ Eh?) and Leandro is a good-looking but very underdeveloped villain: a walk-on’s incredulous cry of ‘a lion man,’ is about as detailed as it gets. I don’t know how much interest any children still watching had in reams of chat about the inevitability of loss, or the portents of Clara’s imminent fate, to ‘blow away like smoke.’ It’s my favourite Capaldi episode so far: beautifully directed (those candle-lit scenes as the Doctor and Ashildr go burgling), beautifully written, beautifully performed. Capaldi’s final look at Clara is heart-stopping.

Next Time: The Zygon Invasion