America is ravaged and a father (Viggo Mortensen) and son (Kodi Smitt McPhee) are alone as they walk through the burned, cold American landscape. The sky is very dark and when the snow begins to fall it is gray instead of white. They desperately want to reach the south where they assume it will be warmer. With only a small pistol to defend themselves against cannibalistic gangs that are ready to ambush everybody along the road, they make their way toward their destination, together with a shopping cart full of food they have scavenged and the clothes they are wearing.