What’s On: ‘Mr. Mercedes,’ PBS’ Voyager Retrospective, ‘Snowfall’ Cracks Up

Mr. Mercedes (8/7c, AT&T Audience Network): “What kind of a monster do you think I am?” barks Brady Hartsfield (aka the villainous Mr. Mercedes) to his boss, glaring from his sunken, haunted eyes. Providing something of an answer to that provocative question, this unnerving episode gives us a better sense of how Brady became a twisted psychopath cut from the Norman Bates pattern. On the other side of the law, retired detective Bill Hodges (Brendan Gleeson) is none too pleased to be patronized by his former police colleagues, who aren’t taking his suspicions seriously: “When did I get so easy to f—ing ignore?” Bill growls. Maybe when he became such an irascible grouch, going into a full rant after a bartender’s casual “No problem.”

The Farthest—Voyager in Space (9/8c, PBS, check local listings at pbs.org): Marking the 40^th anniversary of the Voyager space mission, this two-hour documentary features interviews with more than 20 of the original scientists and team members who helped launch the interstellar exploratory spacecraft. With only a fraction of the computing power of an ordinary cell phone of today, Voyager has sent back to Earth extraordinary images from space, making The Farthest a visual treat. Also aural, with stories about the making of the iconic “Golden Record,” which carries greetings and music to any extraterrestrial being who might encounter it. (The special’s soundtrack of period music includes, naturally, Pink Floyd, which knows something about “The Dark Side of the Moon.”)

Snowfall (10/9c, FX): It took almost the entire first season for a show billing itself as the story of “how crack began” to even mention crack. But since Franklin (Damson Idris) made his discovery during last week’s road trip, his entrepreneurial instincts kick in as he introduces the drug to his own neighborhood, initially giving it away to stimulate demand. Success breeds danger, though, as his crew quickly learns.

Inside Wednesday TV: In a new time period, Bravo’s Odd Mom Out (9:30/8:30c) presents Jill (Jill Kargman) and BFF Vanessa (K.K. Glick) with a medical mystery involving an outbreak of infections on the “Upper Yeast Side.” … On OWN’s Greenleaf (10/9c), Lynn Whitfield as Lady Mae takes charge when her granddaughters are excluded from a debutante cotillion—those are still a thing?—and then Whitfield breaks character to open up on Oprah’s Master Class (11/10c) about her career and family. … Some things never change. When TV Land’s Younger (10/9c) heads to the Empirical Publishing picnic, Liza (Sutton Foster) is once again caught between Josh (Nico Tortorella) and Charles (Peter Hermann).