The new urban cop drama “16 Blocks” is the smartest Hollywood buddy film in a long time. Directed by big budget veteran Richard Donner – of “Lethal Weapon” fame – it’s not as taut as it wants to be, but it also doesn’t try to lull the audience with lazy action movie conceits. Instead it tries to win the audience over with a gritty morality tale presented intensely by an inspired Mos Def and top-notch Bruce Willis.

The movie’s plot is simple, in keeping with its “Serpico”-like story of police corruption. Mr. Willis plays Jack Mosley, a liquor-sodden cop who has to suck on a bottle just to make it through the day.This weakness is the reason for assigning him the seemingly easy task of escorting a petty crook, Eddie Bunker (Mos Def), 16 blocks (title alert!) to a grand jury.

As expected, things go horribly awry. The crook turns out to be anything but an average thug, having witnessed a cabal of bad cops commit a horrible crime. These cops, headed by Mosley’s former partner, Frank (David Morse), want the man dead. And it’s up to Mosley to find his moral compass, lost amid a whiskey haze, and protect Bunker from his former peers. It’s a decision that destroys his career and sets him free at the same time.

What follows is a game of cat and mouse between the two men and what seems to be the entire NYPD. Shot on the streets of New York, “16 Blocks” flirts with being an action film, and delivers plenty of exciting standoffs and close calls. But at its heart, the film is about redemption, and the lengths people go to change.

The lack of gloss and emphasis on grime lend the movie a verisimilitude that harks back to the 1970s – it comes as a relief to watch a movie that trades in textures and close-ups. But for all its intimacy,”16 Blocks” is sometimes torn between being a bloated blockbuster trying to be small, or a scrappy indie film that yearns to be bigger than it is. Ultimately, the result is akin to watching an episode of “Law & Order” – a high compliment, at least from this reviewer.

The truth is,”16 Blocks”is a modestly budgeted thrill helmed with “A-list” talent, proof positive that Hollywood is beginning to lack faith in its recent trend of throwing money and superstar talent at mediocre properties and hoping they eke out a profit. Instead, “16 Blocks” depends on a tightly spun story, a circuitous screenplay by Richard Wenk, and an audience’s natural born love of believable characters who keep them biting their nails. Which is why the best thing “16 Blocks” has going for it is its three leads, each of whom is captivating in a way that excuses any of the movie’s various slow sections.

Hip-hop icon Mos Def turns the usual role of the black, wise-cracking, shuck and jiving sidekick on its ear. He gives us an unexpected portrait of a simple man trying to do the right thing, a street criminal whose only dream is to become a baker … and to tell the truth. Mos Def’s character recalls Dustin Hoffman’s legendary street hustler Ratso Rizzo, only with a heart of gold. Mumbling, smiling, and full of ticks, Mos Def is wonderfully subversive in a portrayal that would have been at best pedestrian, at worst offensive in a lesser actor’s hands.

As the bad guy, underrated character actor Mr. Morse compels as Frank Nugent, a cop who visibly wrestles with his justifications for breaking the law in order to serve it. A thinking man’s Russell Crowe, Mr. Morse plays Frank as a wolf whose compassion momentarily prevents him from fulfilling his selfish and violent actions. It’s a pleasure to see an actor of Mr. Morse’s talent and obscurity share the screen with a rising star and an established one.

Which brings me to Mr.Willis, an aging action star who still to manage to do what Harrison Ford continuously fails at: play a credibly older hero. It’s interesting to watch Mr. Willis’s once youthful, bratty smirk transform into a wizened sneer. Like a latter-day Humphrey Bogart, Mr. Willis plays a flawed hero who wins the day by first defeating his inner demons. Mr. Willis’s Mosley is an unflattering creation. He’s a disheveled heap of a man with a receding hairline, blotchy skin, and bloodshot eyes. Mosley has a limp and a beer belly, and it’s a painful relief to see him grudgingly make noble choices, even if they’re at the last possible moment.

I’d be inclined to suggest that those with an appetite for adult fare wait to watch “16 Blocks” on a small screen when it is released on DVD, but there’s something refreshing in this film’s retro appeal. It suggests that preposterous CGI explosions and stunts alone don’t justify a $10 ticket. Even in a movie market flooded with horror flicks, family films, and special-effects extravaganzas, a smaller, quieter Tinseltown confection with a moral message, a terse screenplay, and excellent actors should lure a few grown-ups to the increasingly alien neighborhood multiplex. It’s worth the money and the time.