A classic AD&D adventure that has been updated for D&D 3.5.
From the cover:
An adventure for levels 8 to 10. An ancient evil has overtaken a once-holy shrine. Thus, a sleepy mountain hamlet becomes a focal point for mysterious disappearances and even stranger legends of what lurks beneath the village. Vile enemies and strange allies, knowing neither sleep nor age, seek to involve the unwary in a titanic battle of good versus evil. Do you dare discover the secrets behind the myths or attempt to exterminate the ancient evil that lies within? Riches, power, glory, and death! All are in: Dark Tower.