In the 1920s, the richest people per capita in the world were members of the Osage Nation in Oklahoma, thanks to the oil that was discovered beneath their land. Then, one by one, the Osage began to die under mysterious circumstances, and anyone who tried to investigate met the same end. As the death toll surpassed more than twenty-four Osage, the newly created Bureau of Investigation, which became the FBI, took up the case, one of the organization's first major homicide investigations.