Also Read: Leonardo DiCaprio's Appian Way Signs First-Look Deal With AppleDiCaprio signed his own first-look deal with Apple last week.Grann’s non-fiction story is set in the 1920s and follows the richest people per capita in the world at the time, the members of Osage Nation in Oklahoma. The oil barons, however, were suddenly killed off one by one, with many more Osage residents dying under mysterious circumstances.