Mt. Fuji threatens to erupt after hundreds of years of dormancy. Ippei accompanies Yuriko on an assignment to investigate the danger, but is stymied when the local constable fails to get citizens to take the danger seriously. Increased volcanic activity causes a huge boulder to be expelled from the bottom of Lake Yoshino, but the stone proves to be not a mere rock, but a living monster, Gorgos.
噴火の兆候を見せる富士山。しかし近隣住民の避難は一向に進まず、樹海の野生児タケルにも話が通じない。彼を探しに樹海へ入った由利子たちは、巨大な岩が飛び出すのを目撃する。
