Respected black cavalry Sergeant Brax Rutledge stands court-martial for raping and killing a white woman and murdering her father, his superior officer.

Rural Mississippi in the 1940s: Lucas Beauchamp, a local black man with a reputation of not kowtowing to whites, is found standing over the body of a dead white man, holding a pistol that has recently been fired. Quickly arrested for murder and jailed, Beauchamp insists he's innocent and asks the town's most prominent lawyer, Gavin Stevens, to defend him, but Stevens refuses. When a local boy whom Beauchamp has helped in the past and who believes him to be innocent hears talk of a mob taking Beauchamp out of jail and lynching him, he pleads with Stevens to defend Beauchamp at trial and prove his innocence.