Initially resistant to becoming a lawman, Wyatt Earp has a change of heart after seeing the sheriff of Ellsworth, Kansas murdered in cold blood by the inebriated brother of town scourge Ben Thompson.

Earp jails Ben Thompson in the hope that his mentally unstable brother Bill will attempt a jailbreak, but the Marshal underestimates the misguided and naive ruthlessness of young Abbie Crandall, who is also determined to help Ben escape.

Wyatt Earp's insistence on patiently stalking the Thompson brothers with a pair of Indian scouts (rather than a posse) doesn't set well with some influential Ellsworth citizens who demand immediate pursuit and capture of the two fugitives.

A quick-tempered former Confederate officer with a grudge against Wyatt Earp threatens to assemble a mob and destroy Ellsworth if Wyatt is not immediately stripped of his badge and run out of town.

Wyatt leaves Ellsworth and becomes the Marshall of Wichita. His first challenge is a group of local vigilantes so intent on hanging a local Faro dealer that they are concealing evidence that he was acting in self-defense.

Bennett hires a gunman to shoot Earp who brags he has faced down Earp before. However, Earp doesn't know him so he suspects there is more to the gunman's story. After trying to determine who the gunman is, Earp decides he must face him.