The film tells the story of Lee Chandler (played by Casey Affleck) who once lived in Manchester; but moved away from his home when tragedy struck. He is now forced to return to his hometown to take care of his 16 year old nephew Patrick.
Spoilers ahead. The problem for Lee however is that a number of years earlier, he had accidentally forgot to put the fire grill on the fireplace. This little mistake led to a burning log falling out of the fireplace, burning up his home, killing his children, and destroying his marriage.
We don’t know this little piece of information as we watch the film, but we see Lee struggle. We see him unable to look his ex-wife in the eyes. We see him trying to be there for his nephew but simply being unable to do so. His grief goes too deep.