When Earp arrives, he learns the spineless town marshal, Cotton Wilson, released the outlaws, but another notorious gunslinger is still in town:  Doc Holliday. Holliday has a grudge against the Earp family, and he refuses to give up Clanton and Johnny. Soon, Holliday and the Earp brothers will form a strange alliance.

Ed Baily is also lurking around Fort Griffin, and he’s gunning for Holliday, who killed his brother. When Holliday kills Baily in self-defense, and a lynch mob is about to string him up, it’s Earp who comes to the rescue and sets Holliday free. They part ways, but back in Dodge City, Earp learns Holliday and Kate are now in town. He orders Holliday to leave, but Holliday is not the man he used to be. He’s hit on hard times, and his health is not up to par. He promises he won’t cause trouble, and Earp relents, allowing him to remain.

Meanwhile, a new high roller is cleaning up at the card table, and immediately breaks the law just by holding the cards. She’s the beautiful gambler, Laura Denbow, and women are not allowed to gamble within Dodge City limits. Earp arrests her for disturbing the peace. At Holliday’s urging, Earp lets her off, but Earp soon becomes smitten by her charm.

When bandits hit the local bank, killing the cashier, Earp finds he’s short on men to go after the outlaws. All his deputies are out of town in a posse with Bat Masterson, so Earp reluctantly turns to Holliday, the one man in town he knows can shoot fast and dead on. With Holliday as his deputy, Earp takes off after the robbers, and the lawman and gunslinger begin an unusual friendship.

Back in Dodge, Holliday learns, his girl Kate left him for Ringo, but Holliday keeps his promise to not cause trouble, and he doesn’t fight Ringo. Earp’s love life, however, is heating up. In fact, he announces he will turn in his badge, and move to California with Laura. But before he can head to his “happily ever after,” he receives a telegram from his brother Virgil saying Ike Clanton is trying to ship cattle he stole in Mexico from Tombstone, the Earp family’s hometown. Laura refuses to go to Arizona, but Earp has an obligation to his brothers. He and Holliday ride to Tombstone—Earp, to finally bring crooked cattleman Ike Clanton to justice; Holliday to settle the score with Ringo for stealing his girl.