Ruthless terrorists smuggle two nukes into the United States through a Mexican drug tunnel in a bold plot to obliterate half of the United States. As world attention is riveted on the fiery destruction they aim to bring to downtown Los Angeles with the first bomb, the terrorists intend to detonate the second nuke 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 bring America to its knees. All that stands in the way of this hellish plan is the determination of a rogue FBI agent, the resourcefulness of a spunky NASA spokeswoman, and the fierce resistance of a crew of drilling rig workers.