1) “Mr. Inbetween” season-opener, 10 p.m., FX, rerunning at 11. Ray is your average bloke — a caring father, a friend who will help you hide your porn or dispose of a body. He’s also a skilled hit man, which is important tonight (shown here), when he’s asked to check up on two less-skilled guys. There’s a droll feeling here that makes the show fun even when nothing happens; then … well, something happens. That’s followed by a rerun that reminds us to always check the trunk before stealing a car.
2) Debate, 8-11 p.m., ABC and Univision. The first two Democratic presidential debates sprawled over two nights and 20 candidates. Now tighter rules (requiring a quantity of donors) have trimmed this one to 10 people and one night. The early front-runners — Joe Biden, Bernie Sanders and Elizabeth Warren — will be there, but now there will be a better chance to focus on key challengers: Cory Booker, Pete Buttigieg, Julian Castro, Kamala Harris, Amy Klobuchar, Beto O’Rourke and Andrew Yang.
3) “Young Sheldon,” 8 and 8:31 p.m., CBS. Here are two pleasantly low-key reruns. The first one shows that Sheldon can be a big problem when he’s sick; the second one shows that he’s also a problem when he’s healthy and building a nuclear reactor. Now, all he needs is some plutonium and …
4) “The Outpost,” 8 p.m., CW. The queen has lots of problems. There’s a siege surrounding her castle … more attackers are expected … Garret seems determined to kill her … and there are all those infected folks, with nasty worms emerging from their tongues. Meanwhile, Talon is with Zed, who’s hard to trust. It’s a big episode, with some good moments, buried by overacting and general excess.
5) “Two Sentence Horror Stories,” 9 p.m., CW. A sweet story about self-reliant housing-project kids is set alongside a nasty one about kidnapping and cannibalism. It’s a good one overall, but needs a warning: This episode stars kids, but all kids (and many grown-ups) should avoid it.