Once upon a time, Louis Hinds (SAMUEL L. JACKSON) and Floyd Henderson (BERNIE MAC) were backup singers for Marcus Hooks (JOHN LEGEND) in the soul trio, Marcus Hooks and the Real Deal. After Marcus went on to a successful solo act, Louis and Floyd tried going out on their own, but after one hit record, they split up in 1979 for a variety of reasons, never to speak again.
That changes with the unexpected death of Marcus, resulting in a tribute concert being scheduled for him, and the powers that be want Louis and Floyd reunited, putting pressure on record label owner Danny Epstein (SEAN HAYES) to pull that off. Floyd is easy to convince, what with him being bored to death in retirement, but Louis wants nothing to do with that or him despite now living a life of squalor following a stint in prison.
But when Floyd tells his former partner they'll be paid handsomely, Louis reluctantly agrees, and the two set off on a cross-country road trip, given help -- at first via phone and then in person -- by Danny's gung-ho intern, Phillip (ADAM HERSCHMAN), who's their biggest fan.
With their destination the historic Apollo Theater, they make various stops to hone their resurrected act. Along the way, and needing money, they stop at the home of a woman they both loved and fought over in the past. Although they find that she's since died, they meet her daughter, Cleo (SHARON LEAL), who one of them might have fathered, as well as her good-for-nothing, drug-dealing, rapper wannabe boyfriend, Lester (AFFION CROCKETT). With her in tow, the two soul men continue on their trip, bickering and fighting as they proceed.