A New Mexico town marshal, Clay Morgan, known as 'Black Patch' since he had lost an eye in the Civil War, takes his job seriously, especially after an old friend, Hank Danner, arrives in town with his wife Helen who formerly loved Morgan. Danner is suspected of a bank robbery and Morgan has to arrest him. Crooked saloon owner, Frenchy De'Vere, sees a chance to get the loot, and he helps Danner escape but has him murdered. Morgan is accused of the killing but nothing is proven and the bank money remains missing. Carl, a young man whom Danner helped when he was being bullied, goes to Helen, who also thinks Morgan killed her husband. Carl gets Danner's gun and starts practicing with it until he becomes the fastest gun in town, with one possible exception ... Morgan, the man he intends to kill.