An entry in the tenfootpole Wavestone Keep contest!
From the publishers description:
The adventure was designed for 4-6 characters, levels 1-2. It took one game session of three full hours to complete, but another hour should be allowed for the troll and goblin encounter in the cave play-testers did not visit. This adventure was originally part of an ongoing campaign.
To fit the mariner theme of the contest, it has been modified from a watchtower on a mountain range to a primitive lighthouse near a shore. Some of the original content has been generalized if it goes beyond the scope of this adventure, which is limited to “nine rooms and eight pages.”
For example, a black dragon posing as a human countess is the antagonist of the original campaign, but her details aren’t necessary to run this stand-alone adventure.