This map was chosen by last month’s vote of the Cartographic Congress (although there was only one member at the time, so it was more of a Cartographic Tyranny, really).
Anyway, the idea of this map is that a necromancer (probably of an aquatic species) who lives in some caves beneath a lighthouse has managed to gain control of the lighthouse keeper (or become the lighthouse keeper, if you prefer) and is doing a really terrible job of keeping the fire lit. As a result, the necromancer has a ready supply of corpses to… you know, necromance. Build an army of the dead, make Frankensteins, whatever they’re into. The rest of the details are up to you!
This map has an annotated version and DM notes for patrons.