Chastain stars as Catherine Weldon, a painter who travels to the Dakotas to paint a portrait of Sitting Bull. During her time there, Catherine becomes involved in the Lakota peoples' struggle over rights to their land.
Although Woman Walks Ahead takes place in the 1890s, Chastain says the film's themes still resonate in 2017. Along with other members of the cast and crew, she became involved in the Dakota Access Pipeline protests that were occurring nearby.
"There were spiritual themes to the movie and they affected us as we were making it," added Susanna White, who directed Woman Walks Ahead. "There were a lot of Native Americans in the crew. There was something transformative about it."
Chastain isn't the only celebrity who fought to halt construction of the 1,172-mile oil conduit across the Missouri River. Leonardo DiCaprio, Mark Ruffalo, and Shailene Woodley also participated in protests, and Woodley was arrested for "trespassing and engaging in a riot," an experience that she recently described as traumatic.
Despite the best efforts of protestors, the pipeline became operational in June.
"The struggles that Sitting Bull and the Lakota people had fought 100 years prior were being relived in our time," White said at the film's premiere.
Chastain has never been shy about sharing her political views. The actress was a vocal supporter of Hillary Clinton during the 2016 presidential campaign and she helped launch We Do It Together, a nonprofit organization that was created to produce and finance films, television, and other media that change the perceptions of stereotypes towards women.