01 - Crypt-City of the Deathless One by Henry Kuttner

Only one man has ever returned from the treacherous Black Forest of Ganymede‚Aîand it shattered his mind. Now, two dubious adventurers have enlisted the reluctant Ed Garth to guide them back to the fabled crypt-city hidden within its depths. As they journey together, Ed is forced to confront the haunting memories of crimes and sacrifices he can no longer recall. Will he unravel the mysteries of his past, or will the darkness consume him once more? - Summary by EVKesserich