"When ex-FBI Agent Patrick Henderson calls in an 'X-Ray Sierra India' incident, the operator doesn't understand. He tells them to pass it up the chain till someone does. That person is Special Agent Kimberley Reynolds. Arriving in snowbound Northern Wisconsin, she finds that a tornado has flattened half the town - and there's no sign of Henderson. Things soon go from weird to worse as neighbours report unsettling sightings and the snow keeps rising - cutting off the town, with no way in or out... As the clues lead to the coldest of cold cases - a cursed expedition into the frozen wilderness - Reynolds follows a trail from the start of the American nightmare, to the horror that still lives on today..."