Rolling in the Deep

From publisher blurb:

In Rolling in the Deep, a group of level-4 adventurers visits Green Shore Hamlet after learning of the atrocities that happened there. A band of ravaging, blood-thirsty sahuagin captured some of their fishermen, leaving fear and uncertainty in its poor place...

The characters track the sahuagin back to their lair. They must find a way to overcome the challenges of swimming underwater and the darkness of the caverns. Glu'Dur'Boog, the leader of the sahuagin, has the power of Targul, an otherworldly entity that demands countless human sacrifices. Not even the heroes are safe in here...