Based on a true story, "At Close Range" takes the morality of the teen movie -- kids are good, adults are bad -- and gives it a bit of an edge, a grounding in reality, that makes it more than just another exercise in glorifying youth.

Brad Jr. (Sean Penn) is a small-town kid, a little wild, perhaps -- he likes hard drugs and soft touches -- but sweet. His father Brad Sr. (Christopher Walken), boss of a burglary ring operating in four states, sees a little of himself in his son, so when the kid asks to join the family business, he's only too happy to tutor him in his trade and offer him its rewards -- drugs, money, liquor and fast cars.

But Brad Jr. is in love, with a girl he saw out of the corner of his eye on Main Street (Mary Stuart Masterson), and love awakens his conscience. When he witnesses the gang's murder of an informant, he decides he's had enough; and when he's arrested, the cops try to make him an informer, too, leading to a chain of events that set father and son in mortal opposition.

While screen writer Nicholas Kazan has a tendency toward dialogue that is "countrified" in a phony way, most of his work is crisp and snappy, and he's structured a story with clear, simple lines. The laconic naturalism of the script, which is matched by a similar style in the acting (particularly Penn's), can begin to drone, but it also balances whatever's excessive in director James Foley's style.

In "At Close Range," Foley (who previously directed "Reckless") may be the first director to successfully adapt music video techniques to a feature film, simply by taking the flash down a notch, and thinking out how shots and sequences fit together over a longer span. The movie has odd, disjointed rhythms all its own, which lull you into a kind of dreaminess. Foley's obsessed with the Pennsylvania landscape and how people fit into it -- his movie is at its best as a mood piece, and stretches of "At Close Range" have a haunting, elegiac quality.

Foley tends to indulge himself, though -- he and his cinematographer, Juan Ruiz Anchia, can be suckers for gorgeousness. And he's hampered by a weakness for the kind of teen operatics that have been a staple of movies from "Rebel Without a Cause" to "Rumble Fish," that ersatz sense that we live life more thoroughly as adolescents, simply because we suffer through it.

This exaltation of the heightened sensitivity of youth leads to Penn's worst performance so far. Without the constraints of a worked-out character reining in his intensity, he plays all generalized emotion, vaguely registering whatever happens to Brad Jr., happy when life is happy, sad when it's sad.

And while the typically fine Masterson finds quirky, ingenious ways to build her scenes, Foley seems to have little skill with actors. The chief casualty is Walken, who despite a considerable reputation as a stage actor has never been much good in movies. Pasty faced and elaborately toupeed, Walken delivers, by conservative estimate, the most bizarre line readings in memory -- his howling, slurred, sometimes unintelligible monologues sound like an Actors Studio homage to Don King. King's hair, by contrast, is his own.

movieag At Close Range, opening today at area theaters, is rated R and contains nudity, graphic violence, and profanity.