1) “Agatha Christie” opener, 8-9:30 p.m., PBS. England’s top novelists often saw wealth from inside and out. As preachers’ kids, Jane Austen and the Brontes were welcome in mansions, but didn’t have the riches. Christie grew up comfortably, but (as a wartime nurse) saw doctors’ arrogance; some of her tales had outsiders (Poirot, shown here, Marple, etc.) solve mysteries, while rich folks floundered. This three-week profile has too much focus on host Lucy Worsley, but remains interesting.
2) “Rudolph the Red-Nosed Reindeer” and “Frosty the Snowman,” 7:10 and 8:15 p.m., Freeform. Unlike most years, “Frosty” will be on cable before its annual CBS run. CBS had “Rudolph” on Monday, but won’t show “Frosty” until Dec. 16. Meanwhile, both cartoons show up often on Freeform; on Monday, it’s “Frosty” at 5:15 p.m. and “Rudolph” at 5:50.
3) More Christmas. “Olaf’s Frozen Adventure” – great character, so-so story – reruns att 7:30 p.m. on the Disney Channel, with “Beauty & the Beast: The Enchanted Christmas” (1997), a made-for-video movie, at 8. At 10, ABC has “The Great Christmas Light Fight”; after a retrospective last week, it airs on two Sundays and then two Tuesdays. And new Christmas movies are 7 p.m. ET on UpTV, 8 p.m. on Hallmark and Lifetime, 8 ET on Great American Family.
4) “The Gilded Age,” 9 p.m., HBO, rerunning at 10 and 11:40. In some moments, we get the bracing beauty of a botanical garden, where a key moment occurs. In others, we have potent reminders that 1883 had more than gardens and gild. Barely surviving bigotry in her Alabama trip, Peggy confronts it at home. And at the steel mill, strikers and troops gird for what could be a lethal encounter.
5) Movies: On the light side, FX has the four “Toy Story” Movies,” at 4, 6, 8 and 10 p.m., and TBS has “A Christmas Story” (1983) at 6:30. Far more serious is “Ben-Hur” (1959), an Oscar-winning biblical-era epic. That’s at noon ET on Turner Classic Movies, followed by fun – “The Man Who Came to Dinner” (1941) at 4, “The Bishop’s Wife” (1947) at 6, “Four Weddings and a Funeral” (1994) at 8 and “Sense and Sensibility” (1995) at 10:15.