Harry Brown is an elderly pensioner who is a decorated Royal Marine, and a veteran of the Northern Ireland conflict. He lives on a London council estate ruled by drug dealers and violent youth gangs, while spending most of his time playing chess with his friend, Len Attwell, at a local pub owned by Sid Rourke. When the hospital phones to tell him that his wife, Kath, is dying, Harry is too late to see her because he is scared to take a shortcut through a pedestrian underpass, which is gang-occupied. His wife is laid to rest next to the grave of their thirteen-year-old daughter, Rachel, who died in 1973.