In the 1920s, the richest people per capita in the world were members of the Osage Indian 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, they began to be killed off. One Osage woman, Mollie Burkhart, watched as her family was murdered. Her older sister was shot. Her mother was then 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—where oilmen like J. P. Getty made their fortunes and where desperadoes such as Al Spencer, “the Phantom Terror,” roamed – virtually anyone who dared to investigate the killings were themselves murdered. As the death toll surpassed more than twenty-four Osage, the newly created F.B.I. took up the case, in what became one of the organization’s first major homicide investigations. But the bureau was then notoriously corrupt and initially bungled the case. Eventually 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. They infiltrated the region, struggling to adopt the latest modern techniques of detection. Together with the Osage they began to expose one of the most sinister conspiracies in American history. A true-life murder mystery about one of the most monstrous crimes in American history.