What’s On: Forest Whitaker on ‘Empire,’ ‘Mr. Mercedes,’ ‘Frontline’ on Korea

Empire (8/7c, Fox): The Lyons’ empire expands with the addition of Oscar-winning actor Forest Whitaker in a new recurring role as “Uncle Eddie,” a music legend who takes in a disoriented Lucious (Terrence Howard) while Cookie (Taraji P. Henson) frets when he goes missing. In musical companion piece Star (9/8c), the girl group clashes with a new label boss (Michael Michele) who wants them to re-brand their image, creating yet more conflict between a rebellious Star (Jude Demorest) and Carlotta (Queen Latifah).

Mr. Mercedes (8/7c, AT&T Audience Network): In the next-to-last episode of this gruesomely macabre Stephen King thriller, the net tightens around the psychotic Brady (Harry Treadaway) as a new lead sends Bill (Brendan Gleeson) and the police to his electronics-store workplace. As desperation sets in, Brady lays plans for his ultimate dark “masterpiece,” while Bill tries to keep Holly (Justine Lupe), Jerome (Jharrel Jerome) and neighbor Ida (Holland Taylor) out of harm’s way.

Frontline (10/9c, PBS, check local listings at pbs.org): In a very timely report, “North Korea’s Deadly Dictator” examines the assassination of North Korean leader Kim Jong-un’s half brother, Kim Jong-nam. While investigating claims that the dictator ordered the murder, the hour also suggests what this says about his and his regime’s goals and capabilities as he engages in nuclear saber-rattling with our own controversial administration.

Inside Tuesday TV: The 36^th season of PBS’s Nature opens with an inspiring portrait of “Naledi: One Little Elephant” (8/7c, check local listings at pbs.org), about an orphaned baby elephant whose caretakers in a Botswana sanctuary help her find her footage while protecting her species from poachers and predators. … Another coming of age on ABC’s Modern Family (9/8c), when Manny (Rico Rodriguez) moves in to his college dorm and tries to avoid a tearful long goodbye with Gloria (Sofia Vergara). Good luck with that. … President Kirkman (Kiefer Sutherland) prepares for a showdown with homegrown terrorist Patrick Lloyd (Terry Serpico) in a melodramatic and preachy episode of ABC’s Designated Survivor, but potentially even scarier are the jokes Seth (Kal Penn) is preparing for the White House Correspondents Dinner.