The Wraith of Derric's Deep (1988)

From Back of Box:

This box set contains "The High Fens Guidebook", the adventure "The Wraith of Derric's Deep", a color poster-sized map of the High Fens District and surrounding areas, and a comparable players' map.

"The Wraith of Derric's Deep" is the second adventure in the "Invincible Overlord" campaign series. As elite scouts in the Overlord's army, your party must enter the mines of Derric's Deep and stop teh hauntings that have even the bravest of miners immobilized with fear. Succeed in this mission, and you will play an integral part in deterring the spread of evil throughout Calandia.

For 4-6 characters, Skill Level 2-4.