Since childhood, John Constantine has had the rare and unwanted gift of seeing the true forms of demons and angels roaming the earth. A failed suicide attempt - a desperate act to escape the torture of an existence he did not understand - has condemned John to Hell, but he is given the opportunity to atone for his sins. He spends his days interceding when demons are attempting to attack the living, while continuing his attempts to end his own life by chain smoking. LA Detective Angela Dodson learns of Constantine's gifts and asks for his help in uncovering the truth about her twin sister Isabel's death, which has been ruled a suicide. Together, John and Angela battle the forces of good and evil as they try to learn what happened to Isabel and prevent the demons of Hell from overtaking humanity.