Fear of the Dark
The Zhentarim ask the party to investigate what happened in one their most important underdark outposts. If the party accepts, they'll have to deal with maddening darkness, grimlocks, an insane kenku assassin and unpredictable mixtures of potions.
A short, fun dungeon romp that is easily adapted to other settings and other patrons. The combination of utter darkness and a villain based on sound makes for fun shenanigans on the side of the DM. Feasible as a one shot for an efficient party.
Two tendays ago, Zhentarim agents were to transport a shipment of rare potions between their Underdark outpost and the surface world. The shipment has yet to arrive, and the outpost is not responding to any sending spells. Growing worried, the outpost’s overseer sends a group of hireswords to investigate and return it to Zhentarim hands.
This particular adventure deals with the delusions of madness of Fraz Urb'luu. It also features Muurmic, the mad kenku first described in the December 2015 issue of Dragon+.