1) “Talamasca” openers, 9 and 10:14 p.m., AMC; also 11:17 and 12:31. Far from her “Downton Abbey” world, Elizabeth McGovern plays a recruiter for a secret group that tries to control supernatural forces. Now she eyes a brilliant and tormented young man (they’re shown here). This Anne Rice spin-off evolves way too slowly, but it’s beautifully written, acted and filmed.
2) “The Simpsons,” 7:30 and 8 p.m., Fox. This is the time to see the show’s brilliant “Treehouse of Horror” shorts. A new half-hour debuted last week and an all-day marathon will be on Halloween (Friday) on FXX. In between, here’s last year’s fairly good episode, starting with political rage consuming Springfield. A new episode (not a “Treehouse”) is at 8.
3) “Maigret,” 9 p.m., PBS. From Sherlock to Poirot, Europe has given us lots unerring crimesolvers. But this strong hour, wrapping a two-parter, reflects Maigret mistakes, now (he didn’t take seriously threats against a brutal mogul) and in his boyhood. Alongside that conclusion, we get a terrific finish to the story of a young “influencer” who vanished.
4) “Tracker,” 8:30 p.m., CBS (but 8 p.m. on the West Coast). This is the midsection of a three-parter that found Colter and his brother (Jensen Ackles of “Supernatural”) probing their father’s death. Now they’ve found a sinister, underground operation called “The Process”; they race to stop it.
5) “It: Welcome to Derry” debut, 9 p.m., HBO. Stephen King’s killer-clown tale seems to have eternal life. It was a two-part mini-series and then two movies. Now we get an eight-part prequel series. As in the movies, Andy Muschietti is directing, with Bill Skarsgard as the villain.