[The] ferocious teacher['s] theory is that only abuse can make an artist great. He repeatedly cites the claim that Charlie Parker became Charlie Parker only because the drummer Jo Jones threw a cymbal at him and almost took his head off. True to the theory, Simmons hits and humiliates his students constantly until one day our boy secretly denounces him and Simmons loses his job. The trouble is that our boy was in agreement with Simmons all along. He didn’t like the treatment but he did believe in it, and the end of the film proves him right. Humiliated one more time by Simmons in a new context, he plays better than he has ever done before, and brings down the house […].
— Michael Wood (London Review of Books)
Under the direction of a ruthless instructor, a talented young drummer begins to pursue perfection at any cost, even his humanity.