Swamped

"All right," the old woman says, suddenly. "Just about done. Youngster, close your eyes, would you? It'll make this next part a lot easier on you."

You don't know what she means, but you decide to comply. Shouldn't your goggles help?

The next thing you know, you don't see anything at all.

It takes a moment to adjust. You can't tell if you're awake or asleep.

"You're asleep," says the old woman. "Well, sort of. I know you've got a lot of questions, and I don't have time to answer all of 'em. Plus there's stuff I just can't talk about, you know? So I put together a little dream where I can explain the basics. You should have time to take it all in while we send you back. It's not just me talking at you, though; if you think about something, I'll tell you about it if I can."

As she speaks, you realize that you're not in the cavern. Where is this?