“Triple 9” has everything going for it, and that’s its biggest handicap.

This tale of gangsters and crooked cops in Atlanta has got a murderers’ row of acting talent — Casey Affleck, Chiwetel Ejiofor, Kate Winslet and Woody Harrelson among them — an alluringly dark premise, and bombastic bursts of greatness. But ultimately, director John Hillcoat (“The Proposition,” “The Road”) fails to meld the storytelling with the film’s ambitious scope, the way Michael Mann so proficiently did 21 years ago with his modern classic “Heat.”

“Triple 9” starts out auspiciously enough, with a pulsating and vividly executed bank robbery that crackles with tension and immediacy as the criminals execute the heist and begin their escape through the busy streets of the gritty city. It’s the kind of drawn-out sequence that can be enough to propel an entire film as you wait for another set piece to top it. There is one other masterfully choreographed raid about midway through, but by then you’re almost too caught up in the confusing who, what, where and why to indulge in the excitement.

Hillcoat, working from screenwriter Matt Cook’s script, trusts the audience to weave together the narratives of its eight main characters by themselves without the help of exposition — a welcome challenge, but a frustrating one as well. There are just so many characters, subplots and motivations to keep track of that it feels more like an extended pilot in the vein of “The Wire” or even “True Detective” than a contained movie.

Essentially, there’s a cabal of mercenary cops (Anthony Mackie, Clifton Collins Jr.) and tattooed, ex-military baddies (Aaron Paul, Norman Reedus, playing brothers) who do dirty jobs for Russian-Israeli gangsters (led by Winslet, packing a thick accent, blond bouffant and vampy press-on nails).

After the opening heist doesn’t go exactly as planned, Winslet’s mob boss demands one last job of her motivated ringleader (Ejiofor), who is forever tied to Winslet’s whims because of the son he shares with her sister (Gal Gadot, who amounts to no more than scantily clad set dressing). Winslet is trying to get her husband out of a foreign prison and the answer apparently lies in Atlanta security facilities.

Have you already lost track? It’s not hard to, and we’re only part of the way there. The crooked cops decide that the only way to carry out the new heist (breaking into a Homeland Security Department facility) is to stage a compelling distraction in another part of town — a “999,” code for officer down. The unlucky sap they settle on to be the sacrificial lamb is the chief’s (Harrelson) nephew (Casey Affleck), who just moved to town and started work at the station.

The problem is that Affleck’s newbie cop turns out to be more than a charity case and the once generally straightforward “999” gets even murkier and more complicated. An unsatisfying third act turn also destroys the promise of the setup.

The talented and endlessly watchable cast helps the confusing story chug along, even after you’ve given up hope of really understanding what exactly is going on or caring about any of the characters in the film. It’s not necessarily the fault of the actors. In fact, for the most part, you just crave more scenes with Ejiofor, Mackie, Harrelson and Collins. Affleck, in particular, proves once again that not only is he the more talented Affleck brother, but could also be one of the greats of his generation if he could just find films and roles worthy of his gift.

“Triple 9” imagines itself a sprawling, nihilistic epic, and it floats along for a while on the shoulders of its prestige filmmaking and cast, but ultimately the storytelling just isn’t up to the task.