Depth Watcher's Pool

From publisher blurb: Depth Watcher’s Pool is a Fifth Edition plug-in adventure for four characters with an average party level (APL) of 11, 14, 17, or 20. This document offers details for each level and makes adjustments accordingly. This adventure takes the heroes underground into a series of tunnels, pools, and temple chambers where fish-humanoid hybrids worship a horrific, multi-eyed aberration called a depth watcher.