Far north of the Arctic Circle, a nuclear bomb test, dubbed Operation Experiment, is conducted. Prophetically, right after the blast, physicist Thomas Nesbitt (Paul Christian) muses, "What the cumulative effects of all these atomic explosions and tests will be, only time will tell." Sure enough, the explosion awakens a 10-metre (33 ft) tall, 30-metre (98 ft) long carnivorous diapsid known as the Rhedosaurus, thawing it out of the ice where it had been hibernating for 100 million years. The only witness to the beast's awakening, Tom Nesbitt, is dismissed as delirious, but he persists.