You, a generic hero, starts an adventure. Sadly, you got sidetracked, and now you're in way over your head. You stumbled into the Underground, a massive underground system of cave cities which the Unholy King, lord of all darkness, rules. You must fight your way through the entire underground, starting from the Dread Lord's Keep, passing through the watery domain of the Many-Armed One, destroy the magical shield protecting the Unholy King by killing the Cultists of Tar-Goroth, the Balrog King, and finally fight his way through a small army of the Royal Guard inside the Unholy Keep. Only then can you dare to challenge the Unholy King!