After witnessing a gangland murder, a young Greek immigrant flees for his life and hides out in a small town, but he soon realizes he's not as safe there as he thought.

A young man visits his fiancé's estate to discover that her wheelchair-bound scientist father has discovered a meteorite that emits mutating radiation rays that have turned the plants in his greenhouse to giants. When his own wife falls victim to this mysterious power, the old man takes it upon himself to destroy the glowing object with disastrous results.

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.