Martin Scorsese unveiled "Killers of the Flower Moon" at Cannes on Saturday, debuting a sweeping American epic about greed and exploitation on the bloody plains of an Osage Nation reservation in 1920s Oklahoma.

Scorsese's latest - starring Leonardo DiCaprio, Lily Gladstone and Robert De Niro - is one of his most ambitious. Adapting David Grann's nonfiction bestseller, it stretches nearly three and a half hours and cost Apple $200 million to make.

Nothing has been more anticipated at this year's Cannes Film Festival than "Killers of the Flower Moon" - a historical epic, a bitter crime film and a Great Plains Western - which appeared to meet those expectations. It drew a lengthy standing ovation and repeated cheers for Scorsese, 80, who premiered his first film at Cannes since 1985′s "After Hours."

"We shot this a couple of years ago in Oklahoma. It's taken its time to come around but Apple did so great by us," Scorsese said, addressing the crowd after the screening. "There was lots of grass. I'm a New Yorker."

The red carpet drew a wide spectrum of stars. Along with the film's expansive cast, attendees included Apple CEO Tim Cook, as well as actors Cate Blanchett, Salma Hayek, Paul Dano and Isabelle Huppert.

Though Grann's book affords many possible inroads to the story, Scorsese and co-writer Eric Roth center their story on Ernest Burkhart (DiCaprio, in his seventh collaboration with Scorsese), a WWI veteran who falls for Mollie Brown (Gladstone), the member of a wealthy Osage family.

Since finding oil reserves on their land, the Osage were then the richest people per capita in the country. But that wealth is closely controlled by appointed white guardians. A series of murders prompts increased panic among the Osage, who are preyed on by a host of greedy killers.

Though Grann's book devoted many pages to the connections between the cases and the birth of the FBI, less time is spent in Scorsese's film on the murder investigations. (Jesse Plemons plays an agent from the just-formed Bureau.) Instead, "Killers of the Flower Moon" captures the manipulation and murders of Native American people through the dynamics in Ernest and Mollie's relationship.

"Killers of the Flower Moon," which is playing out of competition in Cannes, opens in U.S. theaters on Oct. 6.

From The Associated Press