Grade: C+

A real-life incident from 2000 inspired—albeit rather loosely—this flashy but skin-deep story of a teen kidnapped by the well-to-do young thugs to whom his brother owes money. The kid—unwisely, as it turns out—cooperates with his captors, even to the extent of treating his experience as a good-natured lark, until tragedy strikes. Whether it’s intended as a cautionary tale or just a pulpy picture of pampered kids gone bad, “Alpha Dog” has considerable energy, some interesting performances and a powerful climax. Unfortunately, though slick it’s also superficial, a few of the performances are either flat or exaggerated, and an overly long coda, complete with a directorial decision that unintentionally turns high drama into near farce, nearly derails it entirely.

The script by Nick Cassavetes is based on the story of Jesse James Hollywood, who was charged with kidnapping and killing Nicholas Markowitz, the brother of one of his drug customers. Though four of Hollywood’s confederates were tried and convicted, he himself fled, and wouldn’t be tracked down and taken into custody until 2005. (His trial is still pending, and a legal challenge has been raised to the release of the film on the ground that the writer-director was improperly given access to the case file by prosecutors and that its distribution could jeopardize the possibility of a fair hearing.)

But the fact that Cassavetes has taken significant liberties with the record and engaged in a good deal of speculation, as well as reconstruction, is indicated by the change of some names. The Hollywood character here is Johnny Truelove (Emile Hirsch), whose father Sonny (Bruce Willis) is a wiseguy of sorts. Johnny is a small-time drug dealer with a posse of reckless pals, most notably garrulous, well-to-do rebel Frankie (Justin Timberlake) and intense wannabe Elvis (Shawn Hatosy). They, and their other buddies, live what seems to be one long party.

But the atmosphere of drug-fueled hedonism is shattered by one of Johnny’s customers, violent, short-tempered user Jake Mazursky (Ben Foster), who trashes the dealer’s pad in retaliation for being dissed over an overdue payment. Jake’s parents (Sharon Stone and David Thornton) refuse to give him any more help, although his younger brother, quiet, recessive Zack (Anton Yelchin), idolizes him.

Matters heat up when Johnny happens on Zack one day and decides to kidnap him as a way of forcing Jake to pay up. The kid’s not badly treated—indeed, the fact is that the kid enjoys his introduction to the wild life, especially after Johnny puts the easygoing Frankie in charge of him—but when Johnny realizes that the abduction might put him into serious legal trouble, he enlists Elvis to take care of the problem permanently. And anxious to prove himself, he does.

This is a pretty seedy story, and Cassavetes pulls out all the stops in telling it. As writer he jazzes up the narrative with lots of shouting, steamy sexual situations and bursts of violence; he also has characters “testify” directly to the camera about what happened. (It’s one of those recollections at the end, with Stone in makeup so ludicrously unconvincing that it can’t be taken seriously, that deflates the movie badly.) And he directs his own script with every over-the-top trick he can think of—split screens, documentary-style “identifications” of people, times and places, and, of course, a wild visual virtuosity that mirrors the swagger of the characters themselves. The upshot of all this is that the picture generates a good deal of grim energy, not unlike what might have been expected of a seventies exploitation flick, but what results is more heat than light, more bluster than insight. There’s one exception to the rule, in the scene in which Zack, Elvis and Frankie play out the sad conclusion to the kidnapping. Only here does Cassavetes really dig beneath the surface and strike a real emotional chord.

The approach has a strange effect on the cast, some of whom are hysterical and others almost somnolent. At one extreme there’s Foster, who’s so riotously excessive that manic is far too gentle a word for his performance. Timberlake goes for broke, too, but it works better in his case, because he shares so much screen time with Yelchin, whose quiet sensitivity balances the equation (and makes for the most real and affecting character in the picture). Hirsch is restrained as well, but in his case the effect isn’t nearly as strong: he comes across as simply dull, and it doesn’t help that he seems to disappear for long stretches; and Hatosy offers only a generalized sort of fury. There are decent supporting turns from some of the younger members of the large cast—Vincent Kartheiser, Fernando Vargas, Lukas Haas, Dominique Swain—but vets Stone and Willis, as well as a slumming Harry Dean Stanton, seem to be operating on autopilot. On the technical side, cinematographer Robert Fraisse and editor Alan Heim serve Cassavetes’ frenetic style efficiently, as does the pulsating background music.

But all the sound and fury can’t disguise the fact that “Alpha Dog” doesn’t signify much. Its bravado holds the interest, but ultimately it’s about as profound as a piece on “Dateline” or “48 Hours Mystery.”