Just clever enough to rise above the usual fodder, its appealing cast and technical confidence go a long way toward paving over narrative and character lapses. Upbeat box office returns and brisk action in ancillaries loom.

The setting is a North Carolina fishing community where nothing much appears to happen. During the annual Fourth of July celebrations, Helen (Sarah Michelle Gellar) is crowned in a local beauty pageant and goes off to party with her boyfriend, Barry (Ryan Phillippe), and their friends Julie (Jennifer Love Hewitt) and Ray (Freddie Prinze Jr.). Driving home from the revelry, Ray is distracted by Barry's drunken shenanigans and hits something in the road. Stopping to examine the scene of the accident, they discover a bloody, inanimate object.

In the panic of the moment, hotter heads prevail and the teens decide to dispose of the evidence rather than face the prospect of dashing their promising futures at college and acting school. But just as they're about to drop the body into the water, it comes to life, and a brief struggle forever cements their culpability in a murderous act.

A year later, Julie returns to the community after a disastrous first round at an Ivy League college. Waiting at home is a concerned mother and a note bearing the ominous title words. The despondent young woman seeks out her cronies, discovering equally shattered lives. Helen bombed out in New York and is working the cosmetics counter at her family's department store. Ray is eking out a fisherman's life, and Barry still is in a drunken stupor. So much for youthful dreams.

The script lays out the dire consequences of having made the wrong decision. But this is a fleeting notion in the material, quickly segueing into more obvious territory with the appearance of a malevolent presence, whose face is obscured by his fisherman's garb. He disposes of Max -- a classmate who saw the foursome at the side of the road that fateful night and whom the young people suspect wrote the note -- and goes on to terrorize Barry.

The logic behind murdering a nonparticipant and allowing one of the quartet to live is mystifying, if necessary to the thriller's progression as well as to its visceral thrills. A taste of the carnage to come, it's a warning sign that the serious underpinnings of the piece will be sacrificed for genre demands. Remainder of the film plays out as a cat-and-mouse game, with the young women taking the lead in unmasking a killer before he can diminish their ranks.

As with his script for ``Scream,'' writer Kevin Williamson demonstrates adroitness at creating vivid young protagonists. Both a horror buff and a chronicler of contemporary mores, he struggles to mesh his two pursuits with fitful success, bowing to the demands of the genre at the expense of texture and resonance. Ultimately, that limits the picture's appeal, and in the hands of tyro feature director Jim Gillespie much of the wit and playfulness of the exercise is further sacrificed. Gillespie relies on a cool, stylish technical facility to compensate for his apparent lack of connection to the characters.

The leads elevate their prototypes considerably, leaping over seemingly impossible dialogue to convey vulnerability and burdensome guilt. Hewitt and Prinze are particularly good, and Anne Heche is a standout in a supporting role as the hauntingly eviscerated sister of the hit-and-run victim.

There's no question that ``I Know What You Did Last Summer'' is on target for its primary audience. Still, it pulls too many punches and takes too many dramatic shortcuts to maintain the meatier elements introduced at the outset. Its slasher sensibility lays waste to the more chilling psych.