It's been years since the Underground was opened, your friend Frisk returned, and monsters came to live with you on the surface. They all tell stories of the mysterious Underground, that was a world all in its own. You've always been fascinated by monsters and magic. You and a few other monsters, with Frisk as a guide, start to climb Mt. Ebott and the entrance to the Underground.

What happens now?

(Ok so this is a two-way thing, you can fall into the Underground, or continue your story on the surface.)