Published in Frew:
After the big revelations on Eden (see D213 The U-Boat Mystery), the Phantom and Mina discover some discouraging entries in the Phantom's chronicles but are still determined to attempt another entry into the as yet largely unexplored underground chambers.
In the company of Guran and Devil they venture further and further down into the eerie lower chambers in search of a sign of the great experiments allegedly once practiced here, but the truth proves to be much more disturbing...
Watch out for: A warning from the 3rd Phantom
A diary chase in Germany
The adventure started in D213 The U-Boat Mystery
Published in Norway/Sweden: