Effishy

From the introduction: A deranged cleric has kidnapped a town’s leader and stolen a ceremonial effigy ahead of the seasonal festivities. The cleric has been holed up in a discreet cave in the surrounding wilderness. The massive cavern houses a seemingly depthless lake. A string of islands, littered with the ruins of a forgotten fortress, extend from the shoreline. A broken cobble road meanders through ancient archways, over a broken bridge, and up a steep cliff to a fortified tower atop the tallest island.