David Ayer and James Ellroy definitely know  something about dirty cops, at least those in the movies, and they've paired up again for Street Kings. Ayer previously penned the scripts for such films as Training Day and S.W.A.T. He and popular novelist Ellroy even collaborated on Dark Blue (which features Kurt Russell's hands-down best performance ever). Street Kings, a crime saga set on the streets of Los Angeles, looks like it's going to tread cinema's thin blue line for the umpteenth time. However, although the movie isn't without its hokier and more predictable moments, the unusual amount of character development and conflict found throughout the plot lifts the film to a cut above your usual police story.

Keanu Reeves toplines as Tom Ludlow, a corrupt cop whose dirty dealings actually do some good. He's part of a hush-hush division of the LAPD dedicated to doing whatever is possible to deliver justice to the city's scumbags, even if it means altering the crime scene after blowing the culprits to kingdom come. Ludlow is a master of his craft, but after learning that his ex-partner (Terry Crews) has been snitching to Internal Affairs, Ludlow decides to confront him, only to land smack dab in the middle of a supposed robbery that leaves the partner dead as a doornail. It's not long before IA starts sniffing around and pegs Ludlow as a potential suspect, but Ludlow has his own agenda. Teaming up with a young detective (Chris Evans), our troubled hero launches himself headfirst into an investigation of his old buddy's shooting, crossing paths with L.A.'s criminal ilk as well as with  some colleagues who don't want Ludlow digging too deep.

Like 21, Street Kings is an example of what happens when a little extra effort is given to telling a story that would otherwise seem old hat. Instead of simply  going through the motions of a cop drama, Street Kings includes fascinating characters and an interesting central mystery. Ayer's storytelling approach isn't as downbeat and gritty as what we saw in Joe Carnahan's Narc, but it shares a similar knack for casting its protagonists in unflattering lights (not to mention keeping the plot moving at a pretty zippy pace). When one character describes Ludlow as a "guided missile," he means it; once Ludlow gets wind of something fishy involved in his partner's murder, there's no stopping him from getting to the bottom of things. Ellroy and fellow screenwriters Kurt Wimmer and Jamie Moss don't focus the story so much on  gunfights and car chases as they do on the motivations behind them, ensuring that Ludlow's character is deeper than the average action hero.

Still, it's a shame this approach is just half the story in Street Kings. While the screenplay nails Ludlow to a tee, the guy performing the role frequently finds himself gasping for air. As decent as his performance is here, Keanu Reeves doesn't have what it takes to bring to the surface the sort of conflict and inner turmoil a guy like Ludlow would be suffering through. Fortunately, Evans does good work as a cop who warily joins forces with Ludlow; Jay Mohr and John Corbett are fine as two of  Ludlow's corrupt colleagues; and Hugh Laurie (currently the king of smarminess on TV's House) gives a fun but brief performance as a dogged IA inspector. In contrast -- and surprisingly --  recent Oscar winner Forest Whitaker delivers a ho-hum turn as the ringleader of Ludlow's crimefighting circus.

As imperfect as it is, Street Kings finds itself a comfy little place between being a basic, shoot-'em-up action movie and a hard-hitting character study. 

MY RATING: *** (out of ****)

(Released by Fox Searchlight and rated"R" for strong violence and pervasive language.)