Six-hundred-thousand years ago the largest volcano in the Western Hemisphere erupted covering much of what is now the Central United States in a thick layer of ash. The explosion left behind a massive caldera that today is known as Yellowstone National Park. Yellowstone volcanologist Milton Bainbridge discovers Yellowstone is about to erupt again and millions of Americans in thirteen states will parish if they cannot be evacuated from the deadly path of the fallout. Bainbridge mysteriously dies, leaving his assistant, Carlene Carlson, and volcanologist, Jason Trask to save the United States from the worst natural disaster in its history. To make matters worse, a little known terrorist group is planning on using the eruption of Yellowstone to topple the U.S. government. Trask and Carlson face off against a government unwilling to believe an eruption is eminent and a terrorist group that is conspiring to topple the United States in the aftermath of the natural disaster. Caldera is an action packed thriller with a high degree of technical accuracy.