"Only kings understand each other." HBO's new trailer for "Boardwalk Empire" season four, premiering September 8th, highlights the arrival of the magnificently mustachioed Jeffrey Wright as Dr. Valentin Narcisse, "Doctor of Divinity, philanthropist, student of culture and the man who runs Harlem." Will he prove the new complication in Nucky Thompson's (Steve Buscemi) always complicated life? Also notable about the trailer is that, while it features glimpses of Al Capone (Stephen Graham), Gillian Darmody (Gretchen Mol), Richard Harrow (Jack Huston), Nelson Van Alden (Michael Shannon) and Chalky White (Michael Kenneth Williams), there's not a glimpse of Kelly Macdonald's Margaret Thompson. Has she exited Nucky's life for good?