Like many, Mackenzie Garret complains about the weather. It is the hottest summer anyone can remember. The high temperatures are out of control with no end in sight. Until it all changes. Overnight, blue skies become gray, and the hot, humid weather turns to rain, then snow, then ice as the temperature plummets. The entire northern half of the country is thrown into chaos as blow by blow, storm after storm, nature rips into the world, tearing it apart. Towns and cities are evacuated, and Mac and her family are forced to leave their world behind and face a treacherous journey south to safety. Will they make it, or will they be left behind in this new, frozen world?