The Ruins of Karse

From the introduction: A One-Round D&D Legacy of the Green Regent Adventure for 10th-Level Characters ... The Green Regent has returned to Loudwater. With him he carries the coalescence of scorn, the petrified last breath of Karsus, the archmage responsible for the fall of ancient Netheril. Heroes of Loudwater in the city of Waterdeep recovered the stone. He also carries divine knowledge of the nature of the threat that threatens Loudwater and the entire Delimbiyr Crescent.