Undermountain

From the introduction: A One-Round D&D Legacy of the Green Regent Adventure for 8th-Level Characters - Part of the Wintering in Waterdeep Series Gen Con Indy 2004 Version ... The adventure starts when the PCs hear a song drifting out a tavern called the Yawning Portal. Inside they find the bard is none other than Loudwater resident fool, Jekris the Mad. The buffoon Jekris dances in the common hall of the inn, singing his song in perfect pitch. The ditty recounts that the Green Regent entered Undermountain by way of the tavern’s well—the most celebrated entrance into the great massive dungeon below Waterdeep. By the song’s end, he beseeches the PCs to delve into with him into the bowels of Halaster’s maze to find the Green Regent, whom he knows is in dire need of aid.