The Caves of Ikthis

From publisher blurb:

No one wanted to stop in Birkport. It had an odd reputation even before the disappearances started. The mage was worried about his relatives, though, and it turned out he was right to be afraid. The streets are full of strange fish-people and residents are murmuring about ominous things taking place in the caves...

This is a system-agnostic dungeon designed to slot easily into whatever kind of campaign you might be running. Use it as a fishing village, a random wilderness encounter, or the location of important information/items the party needs.