TV tonight: 'Scorpion' guest star, 'Timeless'

Scorpion
CBS, 10 ET/PT

Have you ever noticed that mothers on television tend to either be present and meddlesome or absent and estranged? This week Scorpion brings you the “estranged” type, courtesy of Lea Thompson as Paige’s mom. Well, now mom's back and she has a problem: She’s accidentally stumbled upon a forgotten nuclear reactor — and it’s on the verge of exploding. With so many things to worry about these days, odds are most of us had not considered the need to add “forgotten nuclear reactors” to the list, let alone ones that are about to explode. So thanks for that, Scorpion.

Timeless
NBC, 10 ET/PT

Here’s potentially good news for Timeless fans: Flynn (Goran Vinjic) appears set to finally reveal what he’s up to. And just in time, as he and the team are stuck in hostile territory in 1754 at the start of the French and Indian War, and must unite if they want to survive.

Soundbreaking: Stories from the Cutting Edge of Recorded Music
PBS, 10 ET/PT (times may vary)

This eight-part series kicks off its final three-night run with a look at the birth and impact of music sampling. Soundbreaking may go a little deeply into the weeds for the most casual music fans, but for those who love recordings and have ever wondered how they get made, it’s almost endlessly fascinating.