In the 1920s, the richest people per capita in the world were members of the Osage Nation in Oklahoma. After oil was discovered beneath their land, the Osage rode in chauffeured automobiles, built mansions, and sent their children to study in Europe.
Then, one by one, the Osage began to be killed off. One woman, Mollie Burkhart, watched as her family was murdered. Her older sister was shot. Her mother was slowly poisoned. And it was just the beginning, as more Osage began to die under mysterious circumstances.
In this last remnant of the Wild West, virtually all who dared to investigate the killings were themselves murdered. As the death toll rose, the newly created FBI took up the case, and the young director, J. Edgar Hoover, turned to a former Texas Ranger named Tom White to try to unravel the mystery. White put together an undercover team, including one of the only Native American agents in the bureau. The team infiltrated the region, and together with the Osage they began to expose one of the most chilling conspiracies in American history.