After bringing law and order to Dodge City, now former lawman, Wyatt Earp, and his brothers Morgan, Virgil and young James, plan to settle down in California as gentleman farmers. They’re driving their cattle through Arizona when they encounter Old Man Clanton. Unbeknownst to them, Clanton is the murderous patriarch of the notorious Clanton Clan. Clanton offers to buy the Earps’ herd, but Wyatt isn’t selling.

The brothers make camp and Wyatt, Morgan and Virgil head to the nearby town of Tombstone, leaving James to guard the herd and their belongings. While Tombstone is a boomtown, it is a lawless town, and when the Earps ride in, a crazed Indian is shooting randomly at the residents. No one is willing to stop him, so Wyatt steps in and takes care of the situation. After a time, the men return to camp to a horrific scene.

James, just 18-years-old, is murdered, and the entire herd stolen. Wyatt, vows to avenge his youngest brother’s death, and he knows just where to start looking for the killers—Tombstone. With Morgan and Virgil at his side, Wyatt rides back to Tombstone, and, once again, puts on a badge as the town’s marshal. He deputizes his brothers and gets to work at what he does best, enforcing the law.

In one tense moment, he meets the volatile, now ailing, Doc Holiday in the saloon, but what could have been an explosive situation is diffused when the men acknowledge each other’s skills and commonalities. Wyatt and Doc develop a cautious friendship.

Doc has had quite a few run-ins with the Clanton Clan, but he has a more pressing matter on his mind, at the moment. His ex-girlfriend, Clementine is in town, determined to bring him back to Boston. His current girlfriend, a hot-tempered Latina named Chihuahua, is not pleased. She runs afoul of Wyatt, now keeping the letter of the law, when he catches her helping a professional gambler in a poker game at the saloon where she sings. Meanwhile, Wyatt has become quite smitten with Clementine, and she returns his affection.

When Doc, hoping to give Clementine the slip, leaves town for Tucson, Chihuahua becomes furious, and gets into a fight with Clementine. Wyatt breaks up the brawl, and recognizes the cross around Chihuahua’s neck. It had belonged to James, and was stolen by his killer. After misleading Wyatt, Chihuahua finally admits it was a gift from Billy Clanton.

Now, Wyatt can put faces to the people who killed his brother, and soon with the help of Doc Holiday he will face the shootout of his life at the O.K. Corral.