康斯坦丁（奇诺•李维斯 Keanu Reeves 饰）生来就能看出游走在人间的恶魔与天使，这令年幼时的他十分痛苦，曾经自杀想以这种方式结束自己的痛苦。后来获悉了上帝与撒旦之间有过协议，谁也不能直接插足人间，只能间接诱使人们选择天堂与地狱，而自杀者不得上天堂，他便开始利用自己天赋的超能力帮助铲除人间的恶魔，以此祈求获得一张天堂的门票。 　　一次在帮助一名女警调查她的妹妹的离奇死亡事件时，康斯坦丁意外获释了天使长加百利意图和撒旦的儿子联手统治人间的阴谋。康斯坦丁当然要竭尽全力阻止这一黑暗降临人间……John Constantine is approached by Det. Angela Dodson who needs his help to prove that her twin sister Isabel's death was not a suicide. The dead woman was a devout Catholic and Angela refuses to accept she would have taken her own life. She's asked Constantine for help because he has a reputation for dealing with the mystical. In fact, he is a demon hunter whose sole purpose on Earth is to send demons back to the nether regions. John himself has been to Hell and knows that he is destined to return there on his death - but hopes his good deeds may find him a place in Heaven. As he looks into Isabel's death, he realizes demons are trying to break through to the human world, and his battles lead him into a direct conflict with Satan.