Demons are on the loose and terrorizing Los Angeles in Constantine, a hard-boiled detective story wrapped inside a supernatural thriller starring Keanu Reeves.

As its backdrop, Constantinev, releasing on Feb. 18, uses a unique scenario in the age-old battle between heaven and hell. God and Satan have made a pact to not directly interfere with the planet, but they can send emissaries in human form to try and sway the public to their side.

John Constantine (Reeves) is born with the gift to see these angels and demons which he calls "half-breeds," but rather than embrace this power, he decides to kill himself. His suicide attempt fails and he’s resuscitated against his will, but now he’s committed a mortal sin and his soul is doomed to an eternity in hell.

In an effort to turn the tide, Constantine devotes his life to battling demons and sending them back to hell. He begins to notice a subtle shift in the balance between good and evil as more demons attempt to break through to this world. The changes are somehow tied to a detective (Rachel Weisz) whose twin sister has just committed suicide.

In Constantine, Reeves shows a different side of himself ; he’s cynical, jaded and not at all naïve. The role is a far cry from his role as Neo in The Matrix, although comparisons will be made since Constantine is based on the DC/Vertigo comic book "Hellblazer" and The Matrix series was inspired by the comic book genre.

The film also stars Tilda Swinton, Djimon Hounsou and Shia LaBeouf.

Reeves and Weisz have great chemistry together and director Francis Lawrence uses it well. Intentionally, a kiss between the two never materializes.

"Our idea was that, sure, there might be something that’s there between them, some kind of a sexual energy. But we didn’t want them to get together," says Lawrence, who is best known for the music videos he’s helmed for Britney Spears, Justine Timberlake and Will Smith.

"It’s not what the movie’s about," continues Lawrence. "I think it would have been kind of predictable and kind of cheesy if they’d gotten together, especially if they would have kissed at the end."

Reeves agreed with Lawrence’s approach to the romance.

"It’s one of those things that you can see in the couple. It can be there, and yet it can’t be there because it’s not the time or place," he says.

In most movies about heaven and hell, it seems hell often has a more visually exciting landscape, which also holds true in Constantine. In the script, hell was depicted as a black void but Lawrence said he was determined to create something new.

Working with the visual effects’ supervisor and the production designer, Lawrence created an apocalyptic version of hell that was inspired by nuclear test films from the 1940s.

"[We] just decided that it would be great if the landscape was not only violent with these creatures, but also [had] atmosphere. So we decided that it was kind of an eternal nuclear blast, except nothing ever really gets obliterated because it’s eternal and it’s constantly going," he says.

Constantine keeps the premise of the comic book but not the London location, blonde hair or English accent of the main character. Reeves said he wasn’t familiar with "Hellblazer" before taking the role, but that the physical differences between him and the comic book character are insignificant to the story.

"When I read the script and then familiarized myself with the work, I saw that what was important was really the essence of Constantine. We worked really hard to keep that aspect of it because it’s really what it’s all about," Reeve says.

"That kind of hard-edged, hard-boiled, world-weary, cynical, fatalistic, nihilistic, self-interested [guy] with a heart," says an impassioned Reeves. "I think we did. I hope that fans of the comic don’t feel that we sabotaged something that is so well loved."

Constantine releases in theaters Feb. 18.