Unrest - NWN Side Quest (Chapter 1)
Blacklake: Unrest is a side quest that begins by speaking with Formosa in the southeast corner of Blacklake District and agreeing to help her. Formosa is hard to miss since she is standing on a platform surrounded by a bunch of angry Audience Members (basically inciting a mob).
For this quest you'll have to visit Meldanen's Estate and defeat him - this is something you have to do for the main story quest anyway. If you'd like more information about how to get in Meldanen's Estate and where he's found check out my Blacklake Tensions Rising quest walkthrough.
Once Meldanen has been defeated you'll be given the choice of allowing him to live or killing him. If you allow him to live you'll only get Meldanen's Master Key but if you defeat him you'll get the Key along with Meldanen's Silver Tooth (along with the other items he drops). Giving the Key and Tooth to Formosa will get you the most gold for this quest.
You can also talk with Meldanen too and start the Blacklake: Killing Formosa side quest if you'd like to go the Evil route.