John Hancock is an unhappy and reluctant superhero who is depressed and has drinks heavily. He has saved many lives in Los Angeles, but in doing so, he has no regards for the damages he causes. The public has had enough of Hancock. Then one day, Hancock saves the life of Ray Embrey from being hit by a train. Ray is a public relations executive who now can go home to his wife and child, thanks to Hancock. Ray owes Hancock his life, and he makes it his mission to change his superhero's image. Ray's wife doesn't want Hancock around and makes certain that Hancock knows it.