Terrorists smuggle two nuclear bombs into the United States through a Mexican drug tunnel in a bold plot to destroy the United States. While world attention is riveted on the fiery destruction they aim to bring to downtown Los Angeles with the first nuke, the terrorists intend to detonate the second bomb at the bottom of an experimental NASA geothermal well located in a remote corner of Yellowstone National Park. The nuclear blast will rip open Yellowstone's sizzling caldera, triggering a massive eruption that will obliterate half of the United States.
FBI agent Malcolm Hendricks, special agent in charge of a counterterrorism task force in Los Angeles, thwarts the LA bomb only seconds before it is detonated near USC. He has learned the identity of the terror leader, Abu Hadi al-Maliki, through actions he took in defiance of his superiors in Washington. In recognition of his bold work, the president puts him in charge of finding Maliki and the second nuke, but the only clue Hendricks has to go on is a trail of bodies that ends in Idaho near Yellowstone.
As Hendricks unleashes every resource available to find Maliki and the second bomb, the terror leader and his zealots attack the geothermal site, killing most of the drilling rig workers and many of the journalists who arrive by bus to report on the project. Trained for the mission to operate a drilling rig, Maliki and his commandos begin lowering the bomb two miles to the bottom of the NASA well.
All that stands in the way of the fanatical plot to destroy America are Hendricks' relentless efforts to find him, the resourcefulness of the NASA spokeswoman who brought the doomed journalists to the site, and the brave resistance of the few rig workers who survive Maliki's brutal assault.