Imagine a world where Tiamat was summoned successfully. Where the Princes of Elemental Evil tread unfettered. Where Demogorgon prowls the Underdark with the Wand of Orcus, leaving an army of undead in his wake. Where the storm giants have been cast to the bottom of the Ordning. Where Baldur's Gate has been banished to the Nine Hells. . . . Imagine a world where good has lost and evil prevailed. The Sword Coast has been divvied up by the Zhentarim, the mountain giants of Grudd Haug, the Cult of the Dragon, and many other sinister factions. But above them all looms the Archlich Vecna, who has orchestrated or exploited a series of ever-escalating calamities to conquer the very Realms themselves. Will your players rise to the challenge? Or, will they too, fall before the might of Vecna?