In New York, illegal dumping of waste from atomic experiments causes a centipede to grow to enormous size. It proceeds to break into a subway tunnel and then out onto the streets of the city, causing widespread panic and local destruction. The military are mobilised to try and stop the monster, but their attacks do nothing. A scientist discovers that the centipede is actually absorbing energy from the military’s attacks, causing it to grow faster, and he tries to persuade the General in charge to call off the attacks to give the Scientist time to find a solution. The General ignores the warning, calling in the airforce to try and destroy the Centipede; at the same time, the Scientist realises that he has a prototype energy weapon which should be able to destroy the monster. As the Centipede attacks the Empire State building, the Hero and the Scientist must race to destroy it with the Weapon before the airforce attack causes it to grow to unstoppable size.