On the bottom (first) level, you begin in a chamber in a static layout section in the north. You awaken in a flawed magic circle, and turn upon your creator (a low-level Necromancer). He drops a special plot artifact, the Cloak of Deception, which will allow you to pass for human after leaving the zone.
The levels (apart from the entry room) have a dungeon-type layout, mostly dark corridors and rectangular rooms, and are filled with rats and skeletons. Vaults are possible: circle, amon sul, rat nest, and skeleton mage cabal.
On the top (final) level, there is a Half-Finished Bone Giant, also the work of your (now deceased) creator. This monster can be quite challenging, as you are likely to be only level 3 at the time. You may leave the level without killing the monster, if necessary.