Killers of the Flower Moon[a] is a 2023 American epic western crime drama film directed and produced by Martin Scorsese. Eric Roth and Scorsese based their screenplay on the 2017 non-fiction book by David Grann. Set in 1920s Oklahoma, it focuses on a series of murders of Osage members and relations in the Osage Nation after oil was discovered on tribal land. The tribal members had retained mineral rights on their reservation, but a corrupt local political boss sought to steal the tribal members' wealth.