John Constantine (Keanu Reeves), a chain smoking cynic, has a special gift of being able to see angels, demons, and half-breeds. The movie opens with the discovery of the "spear of destiny" which, according to Catholics, had been the true cause of the death of Jesus. The whole of the movie is based on the concept that Satan's son Mammon wants to have his own hell on earth. Similarly, the half-breed Angel Gabriel wants humans to be worthy of God's upendo kwa proving themselves truly good beings while surviving hell on earth. Gabriel thinks that its unfair for humans to attain God's forgiveness through true repentance because she believes it to be too easy. Hence, she tries to assist Mammon to come to Earth, since he needs divine assistance to do so. Now it's up to John Constantine to save the day.