The Storyline of the game is at follow:
Lately, your dreams have been becoming less discreet...
Visions of strange fortunes and futures ring in your head...
Horrible creatures, eternally cursed to wander...
And such strange fauna, living in worlds not touched for ages...
As well as odd structures, signifying worlds unknown...
You sense you are not the first to have these visions, and you feel weary...
But something tells you that you are different than the rest...
And with that, you descend into The Dungeon...
(The PentPlane Hymn gives the explanation of why you have those dreams and visions.)