1) “Law & Order” season-opener, 8 p.m., NBC. The 21st season begins, a dozen years after the 20th. The long rest, however, hasn’t done it much good; the opener has a fairly flat story about a Cosby-type star and the aftershocks. Sam Waterston, 81, is back briefly as the district attorney, but the courtroom work goes to Hugh Dancy. Anthony Anderson, currently in three series, is back as a cop, with Jeffrey Donovan as his sullen partner and Camryn Manheim as their boss.
2) “Station 19” and “Grey’s Anatomy” return, 8 and 9 p.m., ABC. After a nine-week winter break, the potent combination is back. “Station 19” gets a new chief and deals with crises. Then the “Grey’s” doctors treat several people – including some of their own – injured in a car crash. Meanwhile, Meredith struggles to save the life of David Hamilton, the doctor who brought her to Minnesota in an effort to cure his Parkinson’s disease.
3) “Young Sheldon,” 8 p.m., CBS. Sheldon has savored his usual air of authority in the lab, sometimes outthinking his professor (Ed Begley Jr.). Now a new scientist (Ming-Na Wen) arrives, making him feel unneeded. That starts a new comedy night (after a long winter break) that includes a literal ghostwriter on “Ghosts” at 9 p.m. and Norma’s rude sister (Rondi Reed of “Mike & Molly”) on “B Positive” at 9:30.
4) More comedies. On Fox, “Call Me Kat” (9 p.m.) has Kat help Carter wait in line for exclusive sneakers; also, Randi reluctantly ends up giving advice. Then “Pivoting” (9:30) sees Sarah do the ultimate pivot – agreeing to say yes to new things. Then the 10-minute “State of the Union” (10 p.m., Sundance) starts breezily, before plunging toward Friday’s bittersweet conclusion.
5) “Big Sky,” 10 p.m., ABC. Here’s another show returning from a nine-week break. Stunned by the news of Joseph’s death, Jenny and Cassie search for answers. Also, Max and Rachel decide to tell Jenny about the drugs and money.