Overview: One day on a small island in the south sea, a nuclear explosion takes place. The ISO research planes crash and burn in the high radio-activity. From the remaining records, they learn that in the vicinity of the island there's radioactivity, but not in the center of the island. The God Phoenix is supposed to go to investigate, but in order to overcome the radioactivity belt, they have to use the Firebird on the way in and out. Beauce of this, they request a research ship to supply them with fuel. When they enter the island, there's no radioactivity, and the buildings are also undammaged. But there's nobody around. Joe sees human shapes in a tram which were exposed to very high heat and instantly made molten. He is convinced that a nuclear experiment has taken place. At that time, the walls of the buildings suddenly start to come loose and the radioactivity gets very strong. They get into the God Phoenix and escape from the island, but because of the shock caused by the radioactivity belt not being there anymore, they all lose consciousness. When they wake again, they are on board the research ship. There, Nambu is waiting and says that because of a change in plans they will return to the base in the God Phoenix. Ken is about to obey, but when Ryu says that, for passing the radioactivity belt, they didn't use any fuel, he turns towards Nambu and throws his boomerang. Nambu is Katse in disguise. The strategy of Galactor - namely to pose as Nambu and to be led to the base in the God Phoenix, has failed. Katse escapes in a disc-shaped plane.