Available on DVD: “Kill List”

The best horror movies — the ones that endure and fascinate and frighten us in perpetuity — don’t try to explain evil. There is no logical solution to the events in Stanley Kubrick’s The Shining (a radical difference from Stephen King’s novel, which did lay out a concise but much less satisfying answer). We know little about the creature in Alien, but the monster’s otherness is terrifying. The Exorcist, Rosemary’s Baby, The Blair Witch Project, Halloween, Night of the Living Dead all provided intimations of what might be happening but left the bulk of it for you to decide. Even Alfred Hitchcock’s masterful Psycho, everyone agrees, would have been better without that five-minute epilogue in which a psychiatrist spells out what was troubling Norman Bates.

Kill List, British director Ben Wheatley’s follow-up to his debut Down Terrace, is one of the scariest films I’ve seen in ages, although I cannot in all honesty explain exactly what the movie is about. I could compare it to other pictures (including one in particular that Wheatley is obviously paying homage to here) but that would completely ruin the effect. This film is best approached cold.

There are a couple of things you should know going in, though. Kill List takes its time. At first, it practically crawls, coming on like one of those talky Ken Loach dramas about the working-class blues. Jay (Neil Maskell), an unemployed former soldier, argues with his wife (MyAnna Buring) about money. Jay drinks too much and shouts too much, and when he sits down to dinner with his friend Gal (Michael Smiley) and his girlfriend Fiona (Emma Freyer), tempers flare and arguments explode.

A lot of this stuff, simple as it sounds, is extremely difficult to follow, because the actors’ accents render the dialogue near-unintelligible to American ears, and they keep talking about events in the past (especially something that went down in Kiev during the Iraq war) that we haven’t been let in on. What’s worse, none of these people is remotely likable. The natural response at this point is to start checking your watch and thinking about that episode of 30 Rock on your DVR you haven’t watched yet, because that will be a lot more fun than this dull, dreary film.

Stick with it. Wheatley, who also wrote the screenplay with his wife Amy Jump, knows what he’s doing, and what he’s doing is awesome. The first half-hour of Kill List is intended to be off-putting and discombobulating: You’re supposed to feel a bit baffled when Fiona makes a strange little mark on a mirror for no discernible purpose, then goes back to behaving normally. The movie is laying down important groundwork, giving you a feel for the everyday lives of these characters so when the crazy stuff arrives, the horror is even more hair-raising.

And boy, does it get crazy. Kill List is so carefully constructed and so precise with its shocks that the movie is practically impossible to write about in detail, so I will remain vague. The plot involves hit men, but this is not another Quentin Tarantino rip-off (he would probably love this movie, though). There is a scene of violence involving a hammer that makes a similar sequence in Drive seem like an episode of Home Improvement. Wheatley doesn’t rely on gore to frighten you — this is a much more sophisticated work than torture porn — but when blood is spilled, you will feel it in your gut.

Halfway through the film, the pace suddenly picks up (you’ll know the scene when you see it) and just when you think you’ve figured out where Kill List is heading, Wheatley schools you by proving you know nothing.

Some critics have taken Kill List to task for its lack of overall logic or its unwillingness to tuck every plot strand into place. But Wheatley is tackling the kind of grand, sweeping evil most movies shy away from, because you can’t just blame it on Satan or a crazy dude or plain old supernatural weirdness. This is a wonderfully dark, twisted and deeply unsettling movie, and the fact that a big chunk of the story is left for you to figure out is a strength, not a weakness. The meek and squeamish can stay home: Everyone else, get ready for some nasty business.