The alien monster comes to the earth and brings a threat to humans. The earth's surface is destructed by alien creatures and humans are forced to live underground. People who are unwilling to live like ants work together to form the World United Government. They make ultimate anti-monster weapons after a 20-year effort and distribute them into each underground city. This is called the "Magnetism Plan". However, just before the final battle, the monster detects the danger and starts to release worm eggs onto the earth's surface to invade underground cities. The Black Falcon Team which is responsible for the Magnetism Plan rescues the residents underground accidentally. They are close to the center of the battlefield and human fate is up to them.