When Petey Greene died of lung cancer in 1984, over 10,000 Washington DC mourners gathered in his honor—the largest gathering of its kind the city had ever seen, save for the deaths of elected officials. If you have no idea who Petey Greene was, or what he did to attract such a devoted following, the biopic Talk to Me aims to set the record straight.

Talk to Me opens in 1966, when Greene (Don Cheadle) is the "drive time" DJ at Lorton Reformatory, where the inmates have made a hero out of Greene, thanks to his sly humor and sharp tongue on the prison's PA system. Straight from the penal system, Greene hustles and cajoles his way into the morning slot at DC's top R&B station, WOL, where he captures the hearts and minds of black Washington by "keeping it real" with straight talk about his own life, politics, and the intensifying climate on the streets. It doesn't hurt the film that Greene's rise to local celebrity is punctuated by the blistering sounds of James Brown, Sly and the Family Stone, and a whole host of other post-Motown soul scorchers.

This first half of Talk to Me is fantastic: Cheadle brings a gleeful relish to the role, as does Hustle and Flow's Taraji P. Henson as girlfriend Vernell. The dialogue is fast and filthy, the wardrobe and sets are deliriously funky, and the entire production is swollen with a smart liveliness and grin-inducing charm.

But after the film's emotional climax, when Greene matures behind the mic and eases the city through the riots following Martin Luther King Jr.'s assassination, director Kasi Lemmons starts painting in enormously broad strokes, and the movie veers into standard (and overlong) Behind the Music territory. Alcoholism, professional falling outs, fleeting fame, redemption—it's all there, as formulaic as it is in every Hollywood biopic of the last decade.

Still, it's hard to have too much ill will for a movie that starts so fiercely; it's just too bad that the film, like its subject, peters out meekly, rather than with the razor-sharp roar that defines its best moments.