The story is set in the famous lawless town of Tombstone, Arizona, at a time when all the worst desperados in the territory gather forces into an outlaw gang ironically called The Cowboys.

The Cowboys number some of the fastest guns and worst reputations in the West. But one day famed lawman Wyatt Earp comes to town with his brothers and their wives, looking for a peaceful place to settle down. But the marauding cowboys make it difficult for anyone to stay out of their way.

Soon Earp's brothers and his old friend Doc Holliday are taking oaths as lawmen. Earp is drawn, against his will, into a spectacular showdown and shoot out with the Cowboys at the OK Corral. But that's not the end of the story; not all of the Cowboys were killed in the gunfight, and Earp finds himself and his family threatened by the outlaws.

When his brother Morgan is killed, Earp finally takes the oath as a U.S. Marshal, deputizes some renegade outlaws, and sets out to clean up the town of Tombstone once and for all...