There is a remarkable central action set piece in John Singleton’s new quasi urban Western “Four Brothers” that literally knocks the socks clean off. Three of the four Mercer brothers; hothead Bobbie (Mark Wahlberg), meaty ladies’ man Angel (Tyrese Gibson), straight-up family man Jeremiah (Andre Benjamin); are trapped by masked gunmen inside their recently murdered mother’s family home. Youngest brother Jack (Garrett Hedlund) is pinned down precariously besides a snow bank, all three of his older foster siblings doing everything to make sure he comes out of this skirmish alive.

It’s a brutally brilliant sequence, Singleton unleashing so much tightly controlled sound and fury the rising cacophony of violence almost becomes kinetically poetic. Everything during this tense ten minutes clicks. Peter Menzies, Jr.’s camerawork is rhythmically forceful while Bruce Cannon and Bill Fox’s editing rattles smartly like a machine gun letting off controlled bursts of adrenaline. At the helm, Singleton does no wrong, building the scene with a passionate frenzy sizzling with magnetic energy, pulsing and contracting things this way and that like an athlete’s heartbeat slowly accelerating towards the finish line.

This is unquestionably the movie’s highpoint, an action sequence of such magnificence other filmmakers thinking of making their own blood-splattered thriller should sit back and take notes. It is also the only reason to see the film, because for all of Singleton’s confidence pulling the strings and the quartet of strong performances at its core “Four Brothers” is still nothing more than a half-baked disappointment. It’s a decent stripped-down B-movie idea undone by a turgid and remarkably unimaginative screenplay the likes of which has, unfortunately, become all-too familiar in this unfortunately substandard summer of sameness.

And it is a good B-movie idea. John Wayne even used it back in 1965 for his heroically aggressive revenge Western “The Sons of Katie Elder,” only in his case the reunited brothers came together to avenge the death of their strong-willed father not a saint-like mother intent on saving every hardscrabble kid in Detroit. No matter, it’s still an immediately involving concept, the loss of a parent – even a foster parent – by foul means enough to get even the most blasé heart bleeding for vengeance. The moment Wahlberg walks onscreen you know the notion works, the painful fury etched into every line and hair follicle upon his face so palpable I was grieving even before the first words of condolence were spoke.

Too bad screenwriters David Elliot and Paul Lovett only get the mechanics of the story right and nothing else. This is one of the most painfully pant-by-numbers screenplays I’ve seen in ages. Every cliché in the book gets thrown at the screen; no twist constructed in obvious familiarity goes unturned. Sure Singleton unleashes some grand, archetypical Western images, but so many of them – including a climactic, virtually impossible out-of-nowhere one by Wahlberg – are so silly the resulting effect is far more laughable than moving.

Good thing the actors are so great, for very little else here actually is. Benjamin, a.k.a. Andre 3000 of OutKast, continues to impress as actor. Gibson oozes sexy sensuality ad Hedlund balances just the right amounts of insecure youthful insecurity as the frequently put-upon little brother. Terrence Howard, recently Oscar-worthy in the Singleton produced “Hustle & Flow,” is calm and commanding as a detective sympathetic to the Mercer’s cause while “Dirty Pretty Things” and “Melinda and Melinda” actor Chiwitel Ejiofer eats up the screen as a murderous gang lord out to make the brothers’ lives a living hell.

“Four Brothers” is Wahlberg’s show, however, and for the first time since “Boogie Nights” the actor finally takes the lead role in a motion picture and runs with it. So often brilliant in supporting parts (“Three Kings,” “I ♥ Huckabees”), Wahlberg noticeably wilts when asked to carry the lead load (“Planet of the Apes,” “The Truth about Charlie,” “The Italian Job”). That does not happen this time. The former Funky Bunch front man rules the Mercer roost filling the shoes of older brother Bobbie with fiery panache, commanding the screen and the picture with a steely-eyed authority that can’t help but connect. It’s a stunning turn, one the film desperately needs, and if the script wasn’t so inept I’d almost say it was worth the price of a matinee admission to witness it.

But the script is inept and “Four Brothers” just ends up being the next entry in a long line of Singleton frustrations. Don’t get me wrong. The man is singularly talented but he’s just spinning his wheels with this. “Boyz N the Hood” will forever be a classic; “Baby Boy” will always be worth talking about, but other than those, even when the director stretches (“Rosewood,” “Higher Learning”), nothing quite connects. Now he seems more than happy making glossy studio fares like “Shaft,” “2 Fast 2 Furious” and this, leaving the risky stuff to people like Craig Brewer (the man behind “Hustle & Flow”). While it is commendable Singleton wants to do all he can to get directors like Brewer heard, it is about time he put as much effort into his own works as he does for the works of those he produces.

If you’re a fan of the actors or unfamiliar with the genre I’m sure there’s probably a good time to be had somewhere in all of this. Heck, that central action showdown is so good I’m almost willing to turn a blind eye to the main silliness of everything else myself. Unfortunately, though, I can’t, and as much as I’d like to show “Four Brothers” some love the best I can really do is tell Singleton, Wahlberg and their gaggle of multiethnic foster kids better luck next time.

Film Rating: êê  (out of 4)