Fireplace Level

The Fireplace Level was a large underground complex of rooms initially built by the noble Gost family of Waterdeep for storage and movement of goods in secret. It was eventually abandoned and forgotten by most surface dwellers after it became the home of a number of ghosts. The vampire lord of Waterdeep, Artor Morlin, later claimed it as one of his lairs. It was named by the Company of Crazed Venturers when they discovered an entrance to it via a fireplace flue located in the Dungeon of the Crypt.

Location
This complex of rooms was excavated out from beneath the Gost family villa and an adjacent warehouse (that eventually became the Grinning Lion tavern), about below the surface. The Gost villa was located in the North Ward on the northwest corner of the intersection of Golden Serpent Street and Geltoon Street.

Structure
In the, or shortly thereafter, the entire underground structure was warded to prevent the escape of ghosts. The "Ghost Cage" was a rectangular parallelepiped that surrounded the Fireplace Level beyond the outer walls, comprised of walls of force that overlapped with no gaps except at the three exits. These walls existed on both the Ethereal plane and the Material plane and formed a box approximately by  and of sufficient height (at least  ) to encompass the floors and ceilings. The three Material plane exits were warded with ghostbane traps—a combination of alarm and antipathy spells that automatically reset if triggered.

The entire complex was carved out of the granite upon which Waterdeep sits. Interior walls were typically thick and made of masonry, with doors made from solid oak  thick. The doors were reinforced with metal bracing and each had a steel inlay depicting the the coiled snake motif that was the Gost family insignia. Careful examination revealed a small hole that connected the mouths of the snakes on either side of the door. Each doorway was crowned with a semicircular arch.

Entrances & Exits
There were three physical passages through the walls of force, each wide.