Forgotten Realms is the best campaign setting for D&D.
Forgotten Realms WAS the best campaign setting for D&D...until they took a giant diarrhea shit all over it and fast forwarded everything 100 years. I can't even stand reading the books anymore, and up to that date I had religiously read every single one of them.
Zhentarim, raiding the Dalelands. Sounds like it might be set in the prior time periods.