Viggo Mortensen and Smit-McPhee deliver great performances but it doesn't really hook you up.
A father and his son walk alone through burned America. Nothing moves in the ravaged landscape save the ash on the wind and water. It is cold enough to crack stones, and, when the snow falls it is gray. The sky is dark. Their destination is the warmer south, although they don't know what, if anything, awaits them there.
In a moment the world changed forever.