When singer Nina Simone was introduced to Martin Luther King Jr. her first words to him were "I'm not nonviolent!" Recounted in this documentary, the King anecdote sums up Simone's white-hot anger over racial injustice, which consumed her as she rocketed to stardom in the 1950s and burst into flame after she moved to New York and fell in with James Baldwin, Lorraine Hansberry, and Langston Hughes. Simone was a diva of the first order, notorious for scolding audience members and stalking offstage; in one interview clip she says she wants her listeners to be "confronted with who I am." Writer-director Jeff L. Lieberman takes Simone at her word by portraying her chronic resentment as a tangle of racial anger, professional frustration, and bipolar disorder. The performance clips are woefully short, but even the few seconds meted out for each song provide ample evidence of her stylistic versatility and volcanic emotion.