Strange phenomena surface around the globe. The skies ignite. Terror races through the world's major cities. As these extraordinary events unfold, it becomes increasingly clear that a force of incredible magnitude has arrived. Its mission: total annihilation over the Fourth of July weekend. The last hope to stop the destruction is an unlikely group of people united by fate and unimaginable circumstances.

After years of increases in the greenhouse effect, havoc is wreaked globally in the form of catastrophic hurricanes, tornadoes, tidal waves, floods and the beginning of a new Ice Age. Paleoclimatologist Jack Hall tries to warn the world while also shepherding to safety his son, trapped in New York after the city is overwhelmed by the start of the new big freeze.

Dr. Adrian Helmsley, part of a worldwide geophysical team investigating the effect on the earth of radiation from unprecedented solar storms, learns that the earth's core is heating up. He warns U.S. President Thomas Wilson that the crust of the earth is becoming unstable and that without proper preparations for saving a fraction of the world's population, the entire race is doomed. Meanwhile, writer Jackson Curtis stumbles on the same information. While the world's leaders race to build "arks" to escape the impending cataclysm, Curtis struggles to find a way to save his family. Meanwhile, volcanic eruptions and earthquakes of unprecedented strength wreak havoc around the world.