A dungeon and wilderness exploration adventure for 8th-level characters The island penal mining colony of Deepmar off the north coast of Cheliax has provided the infernal House of Thrune with a steady supply of valuable crystals for decades, but now all contact with the island has ceased. Sent to the isolated island to investigate, the heroes must explore the eerily abandoned mining colony and the surrounding island to discover what sinister threat has silenced the settlement and interrupted the steady flow of minerals from the colony's mines.

Can the heroes discover the truth behind the disappearance of the island's inhabitants and get the rich resources of Deepmar flowing to the mainland again, or will they too vanish, never to be heard from again?