The general gist is that the adventurers are of divine parentage, but don't know of it, as they are born into the world as orphans, and that they were put there because of hell trying to take over the surface through demonic spires and goblin civilizations, with vaults being prisons for tainted angels, spires housing damned dead, goblins, and a demon overlord, with a sealed entrance to the roof of hell.
The roof of hell is pretty much just the DF hell that separates the earth and the actual hell.
http://puu.sh/hooHd/b88d2f770a.txtCould you people think of anything I could add to make the campaign more !!FUN!! for the PCs?