It seems like every horror movie these days is "based on a true story." In our cynical age, it's unlikely anyone is walking into "The Possession" thinking that everything on screen really happened. And despite a solidly chill-inducing first hour, its absurd and goofy final act will ensure it.

"Watchmen"'s Jeffrey Dean Morgan stars as Clyde, a successful small-town college basketball coach. Unfortunately, his family life is less of a slam-dunk. He's been divorced from his wife ("The Closer"'s Kyra Sedgwick) for a year, putting a strain on his relationship with his two little girls.

During a rare happy weekend with his daughters, however, the youngest, Emily (Natasha Calis), finds a mysterious wooden box at a yard sale. The girl starts behaving unnervingly different, becoming distant and attacking anyone who attempts to come between her and her treasured box.

As her symptoms escalate and the body count begins to rise, Clyde discovers the box may be the home of a dibbuk, a vengeful spirit hoping to enter the land of the living again. The only hope for his daughter may be an exorcism, performed by a young Jewish priest played by popular Jewish musician Matisyahu (pre-shaved beard and hair).

The first two acts of "The Possession" aren't without faults. Much of the character development revels in clichés – is there any doubt work-obsessed Clyde won't make his oldest daughter's much-anticipated dance performance? – and Danish director Ole Bornedal has a peculiar habit of quick cutting to black in the middle of a scary scene, a technique that subtracts more than it adds.

What Bornedal does exceptionally well, with the help of his screenwriters Juliet Snowden and Stiles White, is escalate the chill-inducing tension. Moths start infesting the house (far more unnerving than "The Apparition"'s mold and knotted clothes), and Emily's behavior grows more unpredictable as the possession gets stronger. She stabs her dad in the hand but is immediately apologetic afterwards as though she doesn't even know how it happened.

For the most part, the film avoids the typical exorcism movie scare tactics. The demon voices are held in check, and strange body contortions aren't to be found. Instead, the fear is based on slowly becoming someone you're not.

The horror builds quite nicely until "The Possession"'s inevitable exorcism moves toward overblown theatrics, involving a seemingly abandoned hospital, a far-too-accessible morgue and a whole bunch of yelling. It gets even more preposterous when the thing possessing Emily turns out to be an actual creature inside of her, trying to claw its way out.

There's actually the basis for a Cronenberg-esque horror film about the fear of the human body and the invasion of the most private property a person can have. The problem, however, is the irritating and overused "based on a true story" gimmick that the film saddles itself with. It isn't just a marketing tactic either; the movie begins with a title screen noting that it's based on a true story that happened over the course of 29 days.

By stating the film is based on a real story, the movie places parameters around itself. The audience expects horror within the bounds of reality, and anything that goes too far seems even more preposterous as a result. The last act of "The Possession" may try to orchestrate a lot of excitement and terror with flickering lights, computer-created demons and bellowing chants, but it's so outside the realm of possibility, the audience wonders why they were ever scared in the first place.