After the asteroid Orpheus in the Asteroid Belt is hit by a comet, dozens of asteroid fragments are sent on a collision course towards Earth, along with a five-mile wide fragment which will cause an extinction-level event. While the United States government engages in political maneuvering, the smaller asteroid fragments preceding the main body wreak havoc on the planet, revealing the threat. The United States has a secret orbiting nuclear missile platform satellite named Hercules, which was designed by Dr. Paul Bradley. It was intended to defend Earth against a threat like Orpheus, but instead was commandeered by the U.S. Armed Forces to become an orbiting weapon now aimed at the Soviet Union. After many calculations, it is determined that the fourteen nuclear missiles on board Hercules are not enough to stop the asteroid.
