In 1947 Chicago, Polish emigrant and bar owner Leonard Chess (Adrien Brody) hires a blues combo that includes guitarist Muddy Waters (Jeffrey Wright) and harmonica player Little Walter (Columbus Short) . Waters' and Walter's success leads to Chess' management of stars Etta James (Beyoncé Knowles), Howlin' Wolf (Eamonn Walker), Chuck Berry (Mos Def) and others. Inevitably, business and personal lines blur as the sometimes-turbulent lives of the musicians play out.