From the ruins of the irradiated wastes emerge bloodthirsty scavengers and a dangerous new breed of creature known as the Changed. Some survivors call them zombies, others say that they're mutants–whatever they truly are, their sole desire is to murder and eat those unaffected.

A small group of survivors from Illinois attempts to escape further south away from the deepening cold of the nuclear winter. Along the way, they discover that the true monsters are not the Changed–the enemy to fear most is their fellow man.