Steven Knight (Locke) is writing the script, with Susanna White (Nanny McPhee Returns) set to direct the story of Caroline Weldon, a woman from Brooklyn in the 19th century who moved to a Native American reservation in the Dakotas to help Sioux chieftain Sitting Bull fight to keep his people's land out of the grasp of the government. Despite vilification and mockery from the press, who labelled her "Sitting Bull's White Squaw", she kept up her campaign, writing constantly to the federal government and eventually living on the land for years with her son.
The story has been waiting for its cinematic moment for several years, and Tom Vaughn (Starter For Ten) was previously attached to make it. But now, with IM Global touting the rights at the European Film Market in Berlin, it looks set to finally become reality.
Chastain will next be seen in Snow White And The Huntsman (2012) prequel, The Huntsman: Winter's War, which arrives here on 8 April.