When cowboy Lefty Brown (Bill Pullman) witnesses the murder of his longtime partner — the newly-elected Senator Edward Johnson (Peter Fonda) — he strikes out to find the killers and avenge his friend’s gruesome death. Tracking the outlaws across the vast and desolate Montana plains, Lefty recruits a young gunslinger, Jeremiah (Diego Josef), and an old friend, a hard-drinking U.S. Marshall (Tommy Flanagan), to help deliver the men to justice. Co-starring Kathy Baker as Johnson's tough-as-nails widow and Jim Caviezel as Lefty's friend, the Governor of Montana.