I'm waiting for the day when the person writing the score in a thriller just gives up and uses the classic "DUN-dun" from "Jaws." I mean, that's about all the subtlety most thrillers have.

Take "Obsessed." Right from the get-go, the very first awkward accidental touch in the elevator, it's obvious Lisa (Ali Larter) has some issues.

If the camera angles and the music don't let you know, that little crazy gleam in her eyes ought to tip you off.

Larter plays the psycho-stalker-lady well. She's got the right mix of delusion, paranoia and demonic edge to make her a walking time bomb of crazy. And Idris Elba is pretty good as the object of Lisa's ¦ "affections." (Like slipping him a little date-rape drug.)

But this is Beyonce's movie.

The chanteuse plays Sharon, Derek's wife, and she does not take kindly to anybody messing with her man or her family.

The majority of the movie is the interplay between Derek and Lisa, showing the audience just how nutters she is.

But Sharon explodes onto the scene at the end of the movie, obliterating the tense but mostly restrained cat-and-mouse play. If you want to see Beyonce chew some scenery, here's a chance to do so without sitting through three hours of show tunes.

It's also refreshing to see a heroine defend herself. All too often, women in thrillers tend to run and hide or only fight back enough to make an escape -- which inevitably fails.

(If you're going to hit and run, you'd better hit until they're not getting back up, then run, ladies.)

Sharon, though, is on the offensive the entire movie. Even Jennifer Lopez in "Enough" got knocked around before she stood up for herself. If you go at Sharon with a two-by-four, she's gonna clean your clock.

Not to spoil things, but the end is a foregone conclusion. The machinations by which it comes about are pretty obvious, too -- and I'm not the type of person who sits in a movie and tries to guess what's going to happen.

"Obsessed" doesn't reinvent the stalker wheel, but it manages to roll along pretty well anyway. Though the dialogue can, at times, be a little stiff, there are enough good performances to make a viewing worthwhile.