But the story is also a parable for the colonization of the United States by people of European origin. On the surface, it portrays a terrible plot against the Osage people in the 1920s after the tribe gained immense wealth following the discovery of oil on their land. Killers of the Flower Moon is a tragedy about America. Thank you! What is Killers of the Flower Moon about? We encourage your comments to help us create the best possible guide. This guide contains our detailed library of content covering key aspects of the movie’s plot, ending, meaning, and more. Welcome to our Colossus Movie Guide for Killers of the Flower Moon.