The Doctor and River in “The Husbands of River Song”

Times end, River, because they have to. Because there's no such thing as happy ever after. It's just a lie we tell ourselves because the truth is so hard.

No, Doctor. You're wrong. Happy ever after doesn't mean forever. It just means time. A little time. But that's not the sort of thing you could ever understand, is it?

Mmm. What do you think of the towers?

I love them.

Then why are you ignoring them?

They're ignoring me. But, then, you can't expect a monolith to love you back.

No, you can't. They've been there for millions of years, through storms and floods and wars and… time. Nobody really understands where the music comes from. It's probably something to do with the precise positions, the distance between both towers. Even the locals aren't sure. All anyone will ever tell you is that when the wind stands fair and the night is perfect… when you least expect it… but always… when you need it the most… there is a song.

So, assuming tonight is all we have left…

I didn't say that.

How long… is a night on Darillium?

24 years.

[she gasps] I hate you.

No, you don't.