From the publisher's website:
In Nithon, you traverse the Radiation Wastes of Yuggoth, encounter creatures and hazards from nightmare as you seek the Forest and City of Nithon. Here lies the Green Pyramid of the Watcher. The Pyramid awakens before your eyes, and you must explore its fearsome depths. Meanwhile, you are in constant threat of being caught up in the battles raging between the Watcher and its spawn versus the Fungi war-cyborgs.