Taylor Sheridan's Yellowstone universe continues to expand - but whatever happened to the planned 6666 spinoff? The popular franchise, which premiered in 2018, introduced viewers to the fictional Dutton family, who own the largest ranch in Montana. While some viewers came for Kevin Costner's portrayal of family patriarch John Dutton - and stayed for the show's other stars, including Luke Grimes, Kelly Reilly, Wes Bentley, Gil Birmingham and Cole Hauser - others were drawn to the dramatic story lines and surprising twists.