Okay, I'm getting a little paranoid here, because I don't want to miss the bonus dungeon. I'm on my second playthrough, and I keep going to Yormgen and the Sage's house at every opportunity, but there's never anyone there, and I'm worried I'll go past the point of return and never get the scene needed.
Every time I go inside the Sage's, there's just this door that says there's a really old lock that can't be opened, or something like that, and there's nobody there.
Can someone tell me at *exactly* what point I need to go to Yormgen? And do I need some kind of item to open that locked door? What be the deal?