The Fog of Waymoor

From publisher blurb:

Welcome to the remote swamp town of Waymoor. After spending a night here, adventurers are greeted by an imposing wall of shifting fog that smells of death and decay, which threatens not only the characters but the entire town. Through a combination of investigation and role playing, characters uncover a dark conspiracy and curse behind the fog. The adventure concludes with a harrowing encounter in an ancient crypt deep within the marsh, where the party must seal away the evil forces that assault the town.

This adventure is intended to be played by four-to-six characters of 3rd or 4th level, and is compatible with fifth edition Dungeons & Dragons.