Jun travels to Antarctica to look into the disappearance of Nomura, a Japanese Antarctic Winter Party member whose last message is, "Peguila is here." They find Nomura's body and his dog, Saburo, who survived by eating native moss. The team finds that moss contains Peguimin H, a poisonous substance for Peguila. As the monster approaches their outpost, they launch a Peguimin H rocket.

Mt. Fuji threatens to erupt after hundreds of years of dormancy. lppei 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.