Seventies. Exploration for Uranium, disease from irradiated  water, the American Indian Movement (AIM) and the "Traditional"  Natives fight against the Tribal government "Guardians Of the Oglala  Nation (GOONs), and the FBIs assistance to the "Goons" by  providing weaponry and other assistance are some of the things that  are referred to in the movie that were true and documented by  Writer/Director Michael Apted (qv) when he was a regular visitor  to the Reservation during that time.