The Road

A man and his young son struggle to survive after a global cataclysm has caused an extinction event. They scavenge for supplies and avoid roaming gangs as they travel on a road to the coast in the hope that it will be warmer. Years earlier, the man's wife gives birth to their son shortly after the catastrophe and she gradually loses hope. When the man shoots an intruder using one of three bullets they have saved for their family as a last resort, she accuses him of wasting the bullet deliberately to prevent her suicide. Removing her coat and hat, she walks into the woods, never to be seen again. Read more on Wikipedia.