In West Virginia, Charley ?Boomer? Baxter (LaSalle) is supervising the placement of mountaintop-removal explosives. As he detonates the TNT, a massive earthquake liquefies the terrain. Within hours, Dr. Amy Lane (Murphy), a government seismologist, arrives at the epicenter. Amy determines that the initial quake has exposed a deep seismic fault that runs across the center of the North American continent and threatens to tear the world in half. Now, Amy and Boomer must race ahead of the massive crack in the earth while devising a plan to stop the devastation and warn everyone in its path.