D&D 5E Planegea Lair of the Night Thing

It is Autumn. Most of the clans of the Great Valley have departed south with the herd animals they depend on for survival. But one small clan lags behind. For seven nights they have been unable to travel, plagued by a terrible monster known as the the Night Thing, which has killed their people and wounded more. Your party answers the call of dwarf chieftain Skarna Two-Axe, begging hunters from neighboring clans to pursue and kill the monster that’s been attacking her clan, and that slayed her son. Starting at the chieftain’s clanfire, the characters uncover mysteries about the creature that can only be fully solved by tracking the awful Night Thing to its lair, which is full of frightening apparitions. As the party ventures deeper into the Night Thing's lair, they'll discover an even deeper menace, and a plot to overthrow the chieftain. Only they can save Skarna and her people from the grim machinations of their powerful enemies!