The trash warrens are in essence piles of trash and rags for you to move through, with thugs to fight off. You'll first meet Anamoli, a collector who harasses you. Remind him about the Lady and he'll back off.

There's a portal to the east, past a series of people to fight. When you go through it you zap to a closed area to the southeast, full of rats. Kill the rats and you can gather their treasure, then return to the place you started.

Eventually, through the various thugs, you'll reach the southeast area, with Bish. Tell him you're interested in talking to Pharod for 1200xp - he'll let you through. Down the hatch, and into the Buried Village!

Planescape Torment Walkthrough
Walkthrough Master Index