From the back of the book:
It has been years since the wizard's tower burned a hellish green flame and the walls fell. For a time, the area lay desolate and quiet. But now the neighboring farms have been raided, the town attacked and even ships traversing the waters near the towering seaside cliffs have been looted and sunk. Strange sounds and ghostly lights have risen from the ruined tower and adventurers sallied forth to quell the dangers and seek fortune. But what they found was a vast labyrinth of uncounted chambers and caverns filled with monster and treasures!
What Depths Zenopus is an adventure designed for six to eight characters of 3rd to 4th level. This module also contains the full tournament version that was originally held at the 10th Annual North Texas RPG Convention. It is designed for use with the First Edition Advanced game system.
An extension of the Tower of Zenopus example dungeon from the Holmes Basic boxed set.