Lower Tombs (Chapter 3 Story) Overview - Baldur's Gate 2
The northern half of this Lower Tombs is part of the main story walkthrough for Chapter 3 if you side with the Shadow Thief guild. When you return to this location during Chapter 6 some things will be different, Bodhi will be found downstairs instead of upstairs and there's no Lassal or Mace of Disruption. To see my Lower Tombs (Chapter 6) Overview page follow the link provided.
Spider Hive: Inside of this building you'll find Pai'Na who is the hive-master of the spiders that live here. Upon entering you'll be almost immediately attacked, all in all it shouldn't be a difficult fight even for lower level characters. Pai'Na will drop a Black Spider Figurine and you'll find a Pale Green Ioun Stone when searching the container in the center of this room.
Mace of Disruption: When you inspect the pool of blood during Chapter 3 you will find a Mace of Disruption in it. This mace is only here during Chapter 3, when you return to this location during Chapter 6 there will be nothing in the pool of blood.
Coffins & Bodhi: During Chapter 3 when you clear out this Vampire lair you'll need to use Wooden Stakes on all 3 Coffins in this room to make Bodhi spawn. The final coffin is filled after you kill Lassal in the torture room.
Lassal: You'll first have to go downstairs and meet Lassal in Bodhi's Chambers after which he will teleport up top and wait for you in the torture chambers, the same location I have marked on my map.