There's only one surprise involved with The Possession, the latest in the undying genre of exorcism movies, but it's a doozy. As it turns out, shockingly, The Possession is almost a good movie, which for this particular subgenre is a real achievement. Not that I say "almost" a good movie, and not a good movie outright; after all, I'm here to write these words, and that kind of surprise would have been intense enough to give me a heart attack. But in the year when The Devil Inside discovered new bottoms of new barrels for the exorcism movie to scrape, "almost" is more than I, for one, had dared to hope for.

Admittedly, my reason for thinking the movie comes as close to working as it does is for the exact reason that some genre fans have been so ready to toss it on the scrap heap: it has a nice, slow, not at all scary beginning, that gives us a good long chance to get to know its characters. The script, by Juliet Snowden & Stiles White, introduces us to the disintegrated Brenek family of upstate New York, three months after father Clyde (Jeffrey Dean Morgan) and mother Stephanie (Kyra Sedgwick) have finalised their divorce. On his weekend with their daughters, Hannah (Madison Davenport), and Em (Natasha Calis), Clyde excitedly takes them to his brand new house in a subdivision so new that there aren't more than a half-dozen other completed homes; the girls are less than enthusiastic, but put up a good effort not to wallow in dad-hating misery. Still, it's obvious to one and all that they take their "real" home to be with Stephanie and her new, practically live-in boyfriend Brett (Grant Show).

We're certainly in trashy genre film territory here, so I want to avoid making any claims for The Possession like it's some kind of great study of the psychological tensions of divorce. But for a trashy genre film, it's a pretty good 'un. Morgan, while not anyone's idea of a top-shelf actor, gives a steady, grounded performance as a man torn by conflicting desires and fears: to prove himself worthy of the family he's lost, to get back at his ex-wife in all sorts of petty, little ways, and to make sure his daughters still love him at any cost. It's a complex enough performance to carry the first half or so of the movie, before any actual horror stuff has begun, and to keep the film securely in the real world and the experience of actual people just trying to make it through the day. The film's director, Ole Bornedal, has suggested that this was the aspect of the story that fascinated him the most, and it's certainly likely that he pushed his actors in this direction, given how much of the movie in the early going is focused on the family dynamic: Sedgwick, though hamstrung by a much more limited part than Morgan, plays the embittered ex-wife role with exceptional dignity and makes the part more than just a snappish antagonist, and the girls... they're not very good, honestly, though the casting director deserves a medal for finding two unrelated young actresses who look so uncommonly like siblings. Anyway, they don't especially need to be great performances, since their characters function largely as the prize in a tug of war between the two adults.

It is possible - easy, even! - to imagine how a demonic possession movie could function as a metaphor for divorce, and The Possession is almost that movie: the whole paranormal affair starts when Clyde buys Em an old wooden box at a garage sale, out of his current inability to say "no" to his children; this box contains a malevolent spirit, and it causes Em to do strange things, like stab people with forks or vomit moths, but since it stays at Clyde's house, none of this strange behavior manifests itself when she's with her mom, so it seems like whatever's bothering her, it has to do with the strained relationship she has with her dad. When he figures out what's going on, rather later in the game than he should (he knows the box is the cause of Em's problems; there are Hebrew characters on the box; and yet it takes, apparently, weeks to bring it to a Hebrew scholar), he can't take steps to help his daughter, since Stephanie has by this point arranged it so that he can no longer have contact with the girls.

On the other hand, The Possession is also a horror movie being made in the 2010s, and that puts a serious limit on how much character drama it can hold; once it becomes increasingly obvious that Em is possessed by a demon - a dybbuk, specifically, though the further into Jewish mysticism the movie goes, the more obvious that the writers stuck Jewish concepts into the Catholic framework of The Exorcist, and called that "research" - the film abandons all of its subtlety and becomes yet another generic horror picture of the loud noises, things slamming around, and cheap tricks with dark lighting variety. Which is only a real problem because Bornedal proves to have no real facility with this type of filmmaking, and never builds up any kind of tension or momentum to the scares; meanwhile, Anton Sanko's string-heavy score is so desperate to make sure we "get" that this is all scary that it tends to squash all the atmosphere out of the thing anyway.

The less said about rapper Matisyahu's big acting debut as the scholar who performs the dybbucism, the better.

I suppose the worst that can be said about the actual possession half of The Possession - other than the irritating fact that the dybbuk concept is used as virtually nothing but a gimmick - is that it offers nothing new without being actively terrible; but coming off of a relatively strong opening act, that does so much to define the characters and make us interested in their fates, the mechanical, bland scares are even more annoying than they are in other, lesser films on the same theme. There's a worthwhile movie in this concept; but The Possession is not that movie, and it must settle for being merely the best dybbuk movie of the modern era, which given that its competition consists entirely of the godawful The Unborn, is a dreadfully weak, corrupted sort of "praise".