Yuriko and Ippei are passangers on the inaugural voyage of the Inazuma; a futuristic bullet train leaving New Tokyo Station for North Kyushu. Mistaking it for Yuriko's case, Ippei accidently brings along the high-pressure container which houses Dr. Aikawa's artifical lifeforrn, M1.

Jun and Yuriko travel to the island of Iwanejima to investigate undersea volcanic activity. A young marine geologist, Dr. Ishii, has theorized that the entire island may soon be in danger of submerging beneath the sea.

Returning from a pilot's conference in Hong Kong, Jun and Ippei's flight aboard a supersonic passenger jet is suddenly interrupted by a strange pocket of turbulence.