How's this for a story premise: God made a pact with the Devil that none of their minions -- angels and demons -- would ever cross over from the ethereal planes of Heaven and Hell into the human plane. But occasionally, the minions break the rules, and it's up to supernatural hero John Constantine (Keanu Reeves) to "deport" them to Hell as punishment.

Pretty badass, right? This is a violent and apocalyptic story, based loosely on the Hellblazer graphic novels by comic book legend Alan Moore. And much to the relief of comic book fanboys everywhere, this adaptation adheres to the heavy, religious-war foundational spirit of Moore's work. But thankfully for the rest of us, we're treated to a heady mix of pulpy dialogue, eerie atmosphere, biblical mythology, and an engrossing story.

So, why is Constantine busy busting otherworldly visitors? As he puts it, he's been to Hell once (after attempting suicide and succeeding), and he doesn't want to go back -- for eternity anyway. He has a gift that allows him to see these unwanted guests, as well as half-breeds (part angel or demon and human); and he uses it to serve as God's exorcist cleaning crew, hoping to bribe his way to Heaven. But as he first crosses paths with cop Angela Dodson (Rachel Weisz) whose twin just committed suicide herself, he knows something's afoot; demons are coming out of the psychic woodwork. Is the end of the world nigh?

Constantine decides to take up investigating Angela's sister's suicide in hopes that he can discover how all these odd happenings fit together. Along the way, he enlists the help of pals: a fallen priest (Pruitt Taylor Vince), a relic-collecting witch doctor (Djimon Honsou), and an occult-version of Q (Max Baker), who supplies him with awesome holy weaponry. Oh, and he has to take a few business trips to Hell and back, which supply some of the coolest visuals of the film. It all builds to one divine climax.

The look of Constantine is by far its strongest suit. Director Francis Lawrence has given us a sinister, film noir Los Angeles that simmers just above the flames of the Inferno, with both good and evil lurking in the shadows as well as sharing tables at nightclubs. And the script crafts a surly, fascinating, and often droll Constantine out of economic quips and inappropriate hand gestures, all the while still managing to make real characters of the freak show that makes up his social circle. The film even sneaks some suggestively saucy exchanges in between the plot-driving demon battles and apocalyptic revelations, just to keep things interesting. Meanwhile, the acting is terrific, particularly among the villains. Tilda Swinton comes off as equally awe-inspiring and terrifying as the powerful angel Gabriel, and Peter Stormare downright swallows the scenery (and steals the show) as the Devil himself.

As you can tell, this flick is a bit over the top, but it is indeed a film version of an even more outrageous and triply insane comic. And once you let yourself fall into its rising hellfire, you'll get caught up in its thrilling storyline, ominous ambiance, and wild and weird action sequences. If you're in, then buckle down with your holy water and crucifixes, and take a ride on this holy rollercoaster.