Six weeks ago, former US Marine Patrick Larkin purchased shares in a massive high-tech, state-of-the-art underground missile silo for his family. It was a decision based on easing his wildest, most unimaginable nuclear fears. But then reality strikes with devastating suddenness, razing cities in a searing flash across the nation, all of it witnessed by terrified Americans on TV and the Internet. No one knows who pulled the trigger. No one knows if the last day on Earth will ever end. But Larkin and his family are the lucky ones--or so they think.