When Deckard Cain returns to the ruins of the cathedral of Tristram, searching for clues to defeat the new machinations of Evil, a flaming harbinger of destruction falls from the heavens, crashing down on the very ground where Diablo once appeared. This fire from the sky will awaken the Prime Evil and summon the heroes of Sanctuary to defend once again the mortal world against the relentless forces of the Burning Hells.