Joe has sneaked alone into a Galactor base, searching for Governor X. A mysterious girl named Cathy appears before him and tells him that Governor X has moved to the volcano Vesuvio. X has indeed moved to a base in the interior of that volcano, a base built by Berg Katse. X gets angry at a town built by people who are using the volcano's energy. He plans to destroy the city with missiles that will destroy the earth's crust. Magma streams into the subway system of the city. Elsewhere, Nambu who is the architects of the city, has a missile installed in the God Phoenix. This missile will solidify magma. He does this in order to save the city. However, they meet resistance from the enemy and the missile is wrecked. Joe intends to activate the magma solidifying device himself by throwing himself into the magma and pressing the switch. Cathy is a cyborg like Joe, and she has fallen in love with him.