123Movies. In this feature-length documentary from FRONTLINE and Retro Report, an unsolved 1960s murder reveals an untold story of the civil rights movement and Black resistance. “American Reckoning” examines Black opposition to racist violence in Mississippi, spotlighting a little-known armed resistance group called the Deacons for Defense and Justice, woven alongside the Jackson family’s decades-long search for justice amid a federal effort to investigate civil rights era cold cases.