Constantine is a 2005 American supernatural action-thriller film directed by Francis Lawrence as his directorial debut, starring Keanu Reeves as John Constantine, with Rachel Weisz, Shia LaBeouf, Tilda Swinton, and Djimon Hounsou. With a screenplay by Kevin Brodbin and Frank Cappello, the film is based on Vertigo Comics' Hellblazer comic book, with plot elements taken from the "Dangerous Habits" story arc (issues #41-46) and the "Original Sins" trade paperback. The character of John Constantine was introduced by noted comic book writer/creator Alan Moore while writing the Swamp Thing (comic book), first appearing there in June 1985.
In 1988, the character of John Constantine was given his own comic book title, Hellblazer, published by DC Comics under its Vertigo Comics imprint. The “Dangerous Habits” story arc of Hellblazer was written by Garth Ennis in 1991, from which the film is partly based. The film, which was met by film critics with mixed reactions, portrays John Constantine as a cynic with the ability to perceive and communicate with half-angels and half-demons in their true form. He seeks salvation from eternal damnation in Hell for a suicide attempt in his youth. Constantine exorcises demons back to Hell in a bid to earn favor with Heaven but has become weary over time. With death looming, he helps a troubled police detective learn the truth about her sister's death while simultaneously unraveling a much larger and darker plot.
John Constantine (Keanu Reeves) is an exorcist who lives in Los Angeles, California. Born with the power to see angels and demons on Earth, he committed suicide at age 15 after being unable to cope with his visions. Constantine was revived by paramedics but spent two minutes in Hell. He knows that because of his actions his soul is condemned to damnation when he dies, and has recently learned that he has developed lung cancer as a result of his smoking habit.
After a case involving a full-fledged demon trying to break onto the "human plane," Constantine seeks an audience with the androgynous half-breed angel Gabriel (Tilda Swinton). He asks Gabriel for a reprieve from death so that he can continue fighting demons, which Gabriel declines. Constantine is told that his exorcisms will not gain him a reprieve from Hell because his motives are selfish. As he leaves, Constantine repels an attack by a full-fledged demon out in the open. This encounter prompts him to meet with former witch doctor Papa Midnite (Djimon Hounsou). While there Constantine also encounters half-breed demon Balthazar (Gavin Rossdale), who informs him that all of Hell is waiting for him to die and that he is the one soul Satan would come to Earth personally to collect. Constantine begins investigating the situation with his associates Beeman (Max Baker), Hennessy (Pruitt Taylor Vince), and Chas Kramer (Shia LaBeouf). L.A.P.D. Detective Angela Dodson (Rachel Weisz) also shows up at Constantine's apartment looking for his help with her investigation into her twin sister Isabel's death. Isabel leapt to her death from the top of a mental hospital, and despite camera footage showing it Angela is convinced that Isabel would never commit suicide. At first Constantine mocks her and denies her request for help, but after demons attack Angela on the street outside Constantine agrees to look into her sister's death. He informs Angela that God and Lucifer are engaged in a proxy war; a standing wager for the souls of all mankind. Neither true angels nor demons can manifest on Earth, but they are allowed to possess and influence humans. Both sides also use "half-breeds" to peddle influence for their cause.
Hennessy and Beeman's findings lead Constantine to the conclusion that Mammon, Lucifer's son, is seeking to create his own kingdom on Earth by breaking through onto the human plane. To do so, Mammon requires a powerful psychic and assistance from God. Balthazar begins killing Constantine's associates and Angela reveals that she and her sister possessed the same gift as Constantine. Angela refused her visions and they went dormant, but Isabel tried to tell everyone about them and was institutionalized for it. Constantine reawakens Angela's psychic ability through a near death experience, then hunts down and interrogates Balthazar who reveals that Mammon has obtained the Spear of Destiny, which has the blood of Jesus Christ encrusted on it, before being killed by Constantine. The psychic Mammon needs Angela, who is abducted by an unseen force and taken to Isabel's hospital to be used as the portal for Mammon’s entrance to Earth. Constantine convinces Midnite to allow him to use "The Chair", an old electric chair from Sing Sing Prison that had killed over 200 inmates. The Chair shows Constantine a vision that the spear was discovered in Mexico and has been brought to Los Angeles. Constantine and Chas head to the hospital and interrupt the ritual, but Chas is beaten to death by an unseen force in the process.
Using incantations and sigils tattooed on his arms, Constantine forces Gabriel to be revealed. Gabriel subdues Constantine immediately and reveals that the plan to release Mammon was theirs. Gabriel laments God’s favoritism towards humans and believes that bringing Hell to Earth will enable those who survive to become truly worthy of God’s love through repentance and faith. Gabriel then throws Constantine from the room and begins to draw forth Mammon. As Gabriel moves to stab Angela with the Spear and release Mammon, Constantine slits his wrists. Time stops as Lucifer (Peter Stormare) arrives to personally collect his soul. Constantine tells Lucifer about Mammon’s plan and Lucifer sends Mammon back to Hell. When Gabriel attempts to smite Lucifer, the angel's power is nullified and their wings are burned off. In return for his help, Lucifer grants Constantine a favor; instead of a longer life, he asks Lucifer to allow Isabel to go to Heaven. Lucifer then finds that he is unable to drag Constantine to Hell, due to Constantine's self sacrifice. Constantine begins to rise into Heaven, and infuriated by the idea of losing Constantine's soul, Lucifer heals his wounds and cures him of his cancer so that he may live again, claiming that Constantine, in time, will be his. Constantine departs with the Spear after resisting the temptation to kill Gabriel, and gives the Spear to Angela instructing her to hide it, then forget it. As he watches her leave, instead of producing a cigarette, he starts to chew on some nicotine gum.
In a post-credits scene, Constantine visits Chas' grave. He leaves his lighter that he always used. When he leaves, Chas appears as an angel with wings and flies upward to the sky. Constantine smiles, shakes his head and leaves.