BARBARA: You don’t care about anyone, do you? Everyone’s just a – a chess piece, to you, now that Susan’s gone. Ian, me –

DOCTOR: My dear Susan –

BARBARA: I am not Susan! Nor am I a piece of Susan, whatever you’ve told the Venusians. Neither is Ian. We’re people – people who are travelling with you, and through no choice of our own. You have a responsibility to us. If you can’t get us home, very well. But at least you can look after us in the meantime. Or if you won’t – if you’re too busy with your ’mysteries' – then we’ll just have to look after ourselves.

He wondered how Susan was getting on, though he – of all people – should know how idiotic the thought was. Susan wasn’t ‘getting on’ now at all; she would be ‘getting on’ in about three and a half billion years’ time. But still the Doctor found himself thinking: a day has passed, two days, she will be with David, they will be planning a wedding in some half-ruined church, choosing a place to live –

And then –

‘How will you tell him, my dear?’

I can’t bear your children, David, my people and yours are not cross-fertile –

Maybe they would adopt a child, one of the many orphans of the terrible war; or more than one child. He imagined Susan, happy in the middle of her huge family, teaching her children Earth-things, half-forgetting her own inheritance. And David growing older . . .

Would she try to disguise it? Dye her hair, perhaps? Put something on her skin to make it dry and wrinkled? How long would it be before she had to admit the truth?

I won’t grow old, David, not for hundreds of years. My people are – different. But I’ll put flowers on your grave, David, flowers on your grave . . .