There’s plenty going on in Darnell Martin’s affectionate tribute to Chicago’s Chess Records, which was instrumental in the crossover of the blues into the mainstream and the invention of rock ’n roll in the fifties. Too much, in fact. “Cadillac Records”—so called because owner/promoter Leonard Chess had the habit of providing big luxury cars to his stable of talent—is at once a multiple musical biography, a soap opera, a cautionary tale and a portrait of massive cultural change. There’s enough material here for a television mini-series, and cramming it into a picture that runs into less than two hours can’t help but make it seem like a Cliff Notes version.

In this telling, the story begins with Chess (Adrien Brody), an ambitious entrepreneur who’s opened a club on the Windy City’s South Side, meeting Muddy Waters (Jeffrey Wright), a Mississippi sharecropper who’s gone north to ply a trade as a bluesman. Without much ado Chess has opened a recording studio and begun making “race” product with Waters—as well as wild-eyed harmonica wiz Little Walter (Columbus Short)—for which he then secures radio play via payola. Before long others join the crew, including master songwriter Willie Dixon (Cedric the Entertainer), growling bluesman Howlin’ Wolf (Eamonn Walker) and the incredibly talented but troubled diva Etta James (Beyonce Knowles). But the label really hits the big-time with the signing of Chuck Berry (Mos Def), whose mixture of blues, country and gyration represents the beginnings of rock and the breakdown of racial barriers among its fans.

But personal difficulties go along with the professional tale. Walter’s and James’s self-destructive drug abuse is explained by father issues—Walter fought with his, and James never knew hers (she believes that her father was pool shark Minnesota Fats, who impregnated her hooker mother). Wolf has a ferocious chip on his shoulder that leads to conflict with Waters, a genial fellow who finds himself strained financially because of Chess’s laissez-faire business practices. And Berry’s liking for underage girls eventually lands him in jail for transporting one across state lines. In the background, the wives of both Waters and Chess (Gabrielle Union and Emmanuelle Chriqui, both underused) suffer from their husbands’ dalliances and workaholic tendencies. And, of course, the times are changing, and a white man not only owning a business on the South Side but living off black talent attracts the attention of some angry elements in the African-American community.

There’s an attempt to impose a degree of coherence on all this by having Dixon make the connections as he reminisces about the past in the fashion of a rambunctious documentary narrator. That ties things together well enough, but doesn’t keep the whole from feeling rushed and episodic—and as a result of the splashy, extravagant style favored by Martin, the production team headed by designer Linda Burton, art director Nick Locke, set decorator David Schlesinger and costumer Johnetta Boone, inevitably woozy and over-the-top. I must leave to others the issue of oversimplification and dramatic license, always a problem in biopics, but it’s probably considerable in this case, given all the balls being juggled here.

On the other hand, this is inherently a fascinating part of music history, and it’s certainly served up with exuberance if not the degree of control that could wrap it up into a fully realized package. The music’s great, of course, and the actors do a reasonably good job of putting it across, through the fact that Peter C. Frank’s overwrought editing gives us only snatches of performances is a drawback. Among the cast, Wright gives Waters a quiet charisma that’s very effective, Walker adds a mischievous glint to Wolf’s simmering rage, and Def brings a touch of ironic fun to the super-confident Berry. Short certainly captures Walter’s nearly demonic frenzy, but isn’t helped by too many fervid close-ups, while Knowles is adequate without fully replicating James’s magnetism and Cedric tries to get by with a generic sort of bluster. As for Brody, he’s merely okay as the small-time operator; one suspects that neither he nor the script conveys the extent of Chess’s duplicitous financial practices or the degree of manipulation he exercised over the label’s artists.

So in the end this “Cadillac” is a somewhat ramshackle jalopy that provides a somewhat sputtering trip down one of the byways of modern pop music, rather than the luxury ride the story really deserves.