The woman never reveals her name, but the episode's end credits identify her as Sylvia Trench (played here by Niamh Marie Smith, who teased the appearance on Instagram on Oct. 4).

The joke here is that Sylvia Trench is clearly done with James Bond and is now writing a love letter to a woman. This is a bit of a reference to the various Bond novels, in which some characters ...

This reversible trench ($898) from the American brand Buck Mason is two coats in one. Half of it was constructed with a khaki cotton fabric, and the other half with a herringbone wool.

But the show has always rediscovered itself. That’s the beauty of “Doctor Who”: it’s built for change but, like the Doctor himself, has always maintained a core sense of its identity.