It’s Muhammad Ali Documentary Season, it seems, with Ken Burns’s four-part series on the legendary champion playing on PBS, and Marcus C. Clarke’s Blood Brothers: Malcolm X & Muhammad Ali currently available on Netflix.

Clarke’s documentary isn’t treading entirely new ground — we’ve had a number of documentaries and fictionalized films dealing at least briefly with aspects of the men’s friendship, most recently Regina King’s film One Night in Miami  — but the intensity of the focus on the fraught three-year relationship, along with the commentary by Cornel West, Ali’s younger brother Rahman, the daughters of Ali and Malcolm X, and many others, make this film compelling.

And frankly, depressing. There’s a tragic irony at the film’s center that’s haunting long after you’ve seen it dramatically presented in the documentary. The friendship of Malcolm X and the dazzling young prizefighter, then known by his birth name Cassius Clay, fresh from his gold-medal Olympic triumph in Rome but already embittered by his return to Jim Crow America, is centered on Malcolm X encouraging Clay in his interest in the Nation of Islam.