The most notorious love letters in American history-supposedly destroyed a century ago-mysteriously reappear, and become the coveted prize in a fierce battle for possession that brings back to life the lawless world evoked in the letters themselves.

Lisa Balamaro is an ambitious arts lawyer with a secret crush on her most intriguing client: former rodeo rider and reformed art forger, Tuck Mercer. In his newfound role as expert in Old West artifacts, Tuck gains possession of the supposedly destroyed correspondence between Doc Holliday and his cousin and childhood sweetheart, Mattie-who would become Sister Mary Melanie of the Sisters of Mercy. Given the unlikelihood the letters can ever be fully authenticated, Tuck retains Lisa on behalf of the letters' own, Rayella Vargas, to sell them on the black market. But the buyer Tuck finds, a duplicitous judge from the Tombstone area, has other, far more menacing ideas.

As Lisa works feverishly to make things right, Rayella secretly enlists her ex-marine boyfriend in a daring scheme of her own. When the judge learns he's been blindsided, he rallies a cadre of armed men for a deadly standoff reminiscent of the moment in history that made Doc famous: The Gunfight at the OK Corral.