Clawing north, navigating the ruined city amidst violent aftershocks, FBI agent Hector Mendoza hopes to reunite with his wife. Assistant U.S. Attorney Nick Dykstra is hell-bent on finding his daughter way uptown at Columbia University -- before a 9/11 conspirator who escaped during the quake finds her first. But the Indian Point nuclear power plant, 40 miles north, is severely damaged. A deadly cloud of radiation is drifting toward the city. The only chance for survival is going down into the subways -- and deeper still.