The fame and success following the Battle of Andro has left ex-Sisterhood mercenary and adventurer Aestelle both wealthy and famous, but also spiritually unfulfilled and disenchanted. Knowing that her actions in the lead up to that battle have awakened an evil in the Mountains of Tarkis, she assembles a group of adventurers from her past to return to the mountains and put right her mistake. At her side are the famed adventurers Ragran the Mighty, a brutal warrior from the Howling Peaks, and Thesilar, an elven archer famed for her role in defeating the orc warlord Thrundak. Also in the band is Z'akke, a gentle and optimistic salamander mage-priest with his own mission, and Valletto, another veteran of the Battle of Andro who is needed once more for his skills as an aeromancer.

Braving the ancient corridors and tunnels of the ancient, long forgotten mountain tombs, the band of warriors struggle onward in the face of the undead, simultaneously threatened from within by conflicting motivations and forceful personalities. The situation for Aestelle is complicated further by the arrival of Khirius, a vampire lord forced to flee by the Order of the Brothermark, and now the unwilling ally of a dark, secretive underground alliance of undead operating within the very heart of Basilea.