From publisher blurb:
The Forgotten Grottoes of the Sea Lords is an OSRIC module designed for 6-10 adventurers of Levels 6-8.
More than a century ago, the evil Sea Lords ruled this region. They were cruel men, devil-worshippers who practiced vile rites and were the terror of folk across the seas. But, like most tyrants, they were at last thrown down, their strong places sacked and destroyed. Now, they are little more than a name of fear and loathing. Little of them remains, but sometimes an isolated hold or other location is discovered, most filled with plunder from decades of their reign of terror.
Your party has acquired a treasure map purporting to show the location of one of the Sea Lords old holds. While most were sacked and plundered long ago, this one seems to have been missed. With luck, perhaps some of their vast treasure remains for the taking!