An aging mountain man reluctantly agrees to join the posse pursuing a murderous outlaw gang, but his real intent is exact a murderous vengeance on the men that murdered his female benefactor.

Jack Sinclair's gang is trying to steal the gold the U.S. Army is transporting on the same train Doc is transporting a seriously wounded Matt to Denver. Festus and Newly commandeer the wagon the gang will use the haul the gold away. Sinclair and most of the gang give chase on foot; the wagon cannot move fast because of the weight of its load. Matt, laying face down, still manages to shoot one of Sinclair's gang. But, in the process, his condition worsens. Meanwhile, the back story of various passengers unfolds, including a priest who doubts his faith.

—Bill Koenig