One of the recurrent lines of dialogue in “Constantine,” in which Keanu Reeves plays a man-in-black style exorcist, is that “The demons stay in hell.” The movie proves beyond all doubt, however, that while that might be true, hell sometimes makes its way into movie theatres, inflicting a heaping dose of punishment on unwary viewers. “Constantine” is a case in point: it’s apocalyptically awful, “End of Days” bad, “The Order” bad, “Lost Souls” bad. Religiously it’s blasphemous, but as a movie it’s just plain lousy.

The movie is based on a series of dark graphic novels called “Hellblazer,” whose devotees will probably understand the convoluted backstory better than ordinary humans like you and me; it’s been adapted by one guy whose only previous script was for a Steven Seagal flick and another whose first script went on to star Hulk Hogan–hardly a solid foundation for excellence; and it’s directed by a fellow whose resume is solely composed of music videos. The mixture doesn’t bode well, and in the event it proves noxious. Reeves plays John Constantine, who’s introduced in the opening as a gloomy, cancer-ridden but still chain-smoking exorcist whose only associates seem to be a dotty, obsessed priest (Pruitt Taylor Vince, looking even plumper and more deranged that usual); Chaz (Shia LeBeouf, surprisingly colorless in this dull wisecracking role), a young cabbie who’s also a wannabe-acolyte; and Beeman (Max Baker), some sort of geek supplier of supernatural goods. As far as an outsider can make out, Constantine once tried suicide but was revived, meaning that he’s doomed to spend eternity in hell (one of the film’s many crude distortions of Catholic doctrine), and is trying to redeem himself through his devil-bashing work. The violence of the initial possession apparently tells him that some big invasion of earth from the underworld is imminent, so he consults with experts–Midnite (Djimon Hounsou), apparently some sort of voodoo priest who now owns an otherworldly night club (where, we later learn, there’s a chair that can take its occupant temporarily to Hades), and the Angel Gabriel (an unconscionably mannered Tilda Swinton), whose role as advisor and schemer is obscure to the very end. But there’s more: Constantine joins forces with Angela Dodson (Rachel Weisz), a sad-faced cop who’s trying to prove that her twin sister Isabel didn’t commit suicide, as people believe. It turns out Isabel is somehow involved in the literally diabolical plot that John is investigating–as a conduit or median, I suppose–and the duo’s efforts to foil it ultimately bring them up against a nasty but natty demon named Balthazar (Gavin Rossdale) and Satan himself (Peter Stormare, doing a mincing, white-suited comic vaudeville turn at the close).

If all this seems confounding, be assured it’s more comprehensible on paper than on the screen. As a result of the gloomy, shadow-filled production design by Naomi Shohan, the similarly dank art direction by Brian Tyler, Philippe Rousselot’s deliberately dark cinematography and the flagrantly florid direction of Francis Lawrence, who’s obviously still stuck in music-video mode (when he finally gets around to using strobe lighting–the nadir of such effects–your heart sinks), “Constantine” is both visually repugnant and virtually impenetrable as narrative. In such a doom-ridden environment Reeves’ “whoa!” mentality seems even more absurd than usual; he expends most of the little acting talent he possesses flicking a cigarette lighter and making sure that the folds of his rain-slicked trenchcoat billow behind him photogenically. He also endures a lot of physical abuse in the course of the picture, getting beaten up and throttled on a pretty regular basis; you may even start feeling sorry for him. But Keanu can take some comfort in the knowledge that the audience suffers more than him. Weisz once again proves an empty presence, and everybody else is reduced to camping and vamping around the principals. The most unrestrained are certainly Swinton and Stormare, though at least they appear to be having fun in their extravagance. Would that we could join them.

“Constantine” is utterly worthless muck, but one of its most offensive aspects is the way it uses–or, more properly, abuses–Catholic dogma and iconography for its sleazy effects. In a tale like this, religion is nothing more than a perverted adornment, a matter of style rather than substance–like the habit so many people have of ostentatiously wearing crucifix necklaces despite the fact that they’re just meaningless ornaments to them. Spreading a thin veneer of Christian symbolism and doctrine (however distorted) over this sort of pagan frightfest should disgust anyone, whatever their faith or lack or it.

But then, the movie as a whole is repulsive, from whatever perspective you look at it. And to make things worse, it’s also boring. Now there’s a damnable combination.