TV column for Thursday, Sept. 21

“The Big Bang Theory,” 8 p.m., CBS.

Back in its second
season – nine years ago -- “Big Bang” put Sheldon in fresh
turf: An attractive grad student (Riki Lindhome) was enamored.
Unaccustomed to attention -- or to women -- he floundered.

This May, the
season-finale brought her back. Now she's Dr. Ramona Nowitzki,
arriving at a tricky time: Sheldon's girlfriend (platonic, except for
once a year) is away at Princeton. Here's a rerun of a great episode,
propelling us to Monday's season-opener ... and then to the
delightful “Young Sheldon.”

“Zoo,” 10 p.m., CBS.

At a time when the
big networks were floundering each summer, CBS took bold strokes:
Each summer had a couple big-deal science-fiction dramas; the first
ones -- “Under the Dome,” “Extant” -- scored well in the
ratings, but recent ones have struggled.

Now this year's
shows are wrapping up. “Salvation” finished its first season
Wednesday; “Zoo” ends its third tonight. The team races to stop
the hybrid creatures from breaching the barrier wall.

ALTERNATIVE: “The Vietnam War,” 8 p.m., PBS, rerunning at 9:30.

The first half of
Ken Burns' magnificent documentary concludes with one of its most
involving people.

John Musgrave joined
the Marines as a teen from small-town in Missouri, filled with
patriotism and idealism. Then he saw the enemy. “My hatred for them
was pure,” he says. “I hated them so much .... and I was
terrified of them.” There was reason to be. In a fierce fight at
Con Thien, most of the unit was wounded (including Musgrave) or
killed. Officials kept insisting that the U.S. was winning.

“Doc Martin” new season, any time,

Most of the time,
this is a low-key drama-with-comedy, centering on a crusty village
doctor. He has a wife (the local teacher), a toddler, an aunt (a
retired doctor) and some pleasantly offbeat neighbors.

The season-opener
also detours toward flat-out, slapstick comedy. The pleasant-but-dim
constable has a beautiful-but-ditzy fiancee; their wedding –
complete with his ailment, her doubts and a medicated vicar – is
wildly funny. That's followed by a mostly serious episode, with Art
Malik as guest star.

Other choices

-- Finales , 8-11
p.m., ABC. A week before their new seasons start, ABC's shows remind
us how the previous ones ended. “Grey's Anatomy” (8 p.m.) has a
patient escape from his room and endanger the rest of the hospital
... “Scandal” (9) has Fitz making big moves at the end of his
presidency ... “How To Get Away With Murder” (10) finally offers
details on the night of the fire and on who killed Wes.

-- “Penn &
Teller: Fool Us,” 8 p.m., CW. After airing reruns all summer, this
amiable magic show has some new hours to show today, Monday and next

-- “Gotham”
season-opener, 8 p.m., Fox. Jonathan Crane – also known as The
Scarecrow – may be back. There's a string of robberies in his stle.
Also, Penguin's crime scheme starts to backfire.

-- “The Orville,”
9 p.m., Fox. The original “Star Trek” was almost an anthology,
shifting in tone from week to week. So after a couple light episodes,
“Orville” moves into its Thursday timeslot with a dead-serious
drama about a one-gender culture. There are a few light, pop-culture
moments, but the drama part – well-meaning, but heavy-handed –
dominates. “Orville” is, as usual, almost adequate.

-- “Project
Runway,” 9-10:33 p.m. Last week's episode (rerunning at 8) involved
designing for good or evil; the new one lets the models having some
control, creating street-style fashions.

-- “Chicago Fire,”
10 p.m., NBC. In a rerun of the season-finale, a warehouse fire
rages. (We'll learn next week if everyone survived.) Chicago Cub
stars Kris Bryant and Jake Arrieta play themselves.