A new film set in the Osage Nation of northeastern Oklahoma – “Killers of the Flower Moon” – is set to be released in October. The film is based on the best-selling 2017 nonfiction book by the same name.

The film, by Academy Award winning director Martin Scorsese, premiered at the Cannes Film Festival in May to rave reviews. The film stars Leonardo DiCaprio, Robert De Niro, Lily Gladstone (Blackfeet and Nimíipuu), Jesse Plemons, Brendan Fraser and John Lithgow.

The book, by author and journalist David Grann, investigates a series of murders of wealthy Osage people that took place in Osage County in the early 1920s after big oil deposits were discovered. The Osage people are awarded the rights in court to the profits made from the oil deposits, and prepare to receive their entitled wealth. But a complex plot is hatched to murder the inheritors. The official murder count would reach 20, but Grann suspects that hundreds more may have been killed because of their ties to the oil. 

The book also details the newly formed FBI’s investigation of the murders, as well as the eventual trial and conviction of cattleman William Hale as the mastermind behind the plot.

In a January interview in Variety, Gladstone said that the input of the Osage Nation “greatly changed the film from what Scorsese had originally envisioned,” and that the collaboration “had positively affected the film.”

“Killers of the Flower Moon” is scheduled to be released in select theaters Oct. 6, before a wider U.S. release Oct. 20 by Paramount Pictures. It is also set for an eventual streaming release on Apple TV+. Watch the film’s trailer here.