Teonna Rainwater’s 1923 storyline features harrowing scenes made all the more difficult to watch by being based on real history. The scenes in the Yellowstone spinoff depict the physical and emotional abuse inside a Catholic boarding school for Indigenous American youth in Montana. Teonna is beaten and brutalized for forgetting small details in her lessons, for speaking her Native language, and for seemingly any excuse Sister Mary can think of for attempting to dehumanize her. Teonna fights back against her oppressors, eliciting more violent reactions from those running what were referred to as Indian Schools at the time.

https://screenrant.com/1923-show-teonna-rainwater-native-american-boarding-schools/