Sympathy for the Baatezu

Description from the front page of the module:

Digging deeper into the dark alleys of Eastfair has cleared up some puzzles, but the sickly dust quickly settles to create new obfuscation. Perhaps it is time to step out for some fresh air. A favour for a favour, new friends may be able to help you help yourself and get to the bottom of this mystery. With the who's and how's covered, it's time to gather up a motive. The pillows and linen are freshly changed, so head on over to The Whirling Dervish and get a good rest, you'll need it. An advrenture for APL 2 - 8. Part Three of the "running with the Baatzu" series.