During WWII, Germans obtain the immortal heart of Frankenstein's monster and transport it to Japan to prevent it being seized by the Allies. Kept in a Hiroshima laboratory, it is seeming lost when the United States destroys the city with the atomic bomb. Years later a wild boy is discovered wandering the streets of the city alone, born of the immortal heart.

During World War II, a shot-down American pilot and a marooned Japanese navy captain find themselves stranded on the same small uninhabited island in the Pacific Ocean.