Oh, no, nothing terrible like that. It's all very well-known what happened.

[She does laugh a little, at that. A reassuring action, to show it isn't so awful!]

A deal was made for love, and as always a city was the price of that deal. So it was taken down from the Surface of the Earth, into the Neath below as a Fallen City, with the changes that come with that. Just like those before it!

This time it was the city of London, so now, it is called Fallen London. That's all.