At Yellowstone National Park, earthquake tremors are common. But today, park scientist Tucker Mayfield detects something different: a disturbing new increase in activity--and intensity... Lurking beneath the park's natural wonders, Earth's largest supervolcano begins to awaken after 640,000 years. If--or when--it blows, two-thirds of the North American continent will be destroyed... Racing against time, Tucker Mayfield mobilizes a team to evacuate all visitors from the park--including his family at the Old Faithful Inn. But when the earthquakes intensify, and the death toll rises, a shockwave of panic spreads across the nation. Troops are deployed, emergency plans activated. But nothing can stop a natural disaster of this magnitude. When the volcano erupts, doomsday begins--and no one gets out alive...