What can I say about this season of “24” (8 p.m., Fox)? If you like thrillers and you’re not watching “24,” you might as well throw your television set out with the trash. It’s not going to get any better than this.

With the exception of a contrived story line about Bauer’s (Kiefer Sutherland) daughter, Kim (Elisha Cuthbert), “24” offers a nonstop onslaught of nail-biting tension.

Now we have the return of both of last season’s very bad girls to complicate matters. On tonight’s “24,” Jack enlists the evil Nina (Sarah Clarke) to get to the bottom of the nuclear conspiracy. And if saving Los Angeles weren’t enough of a worry, President Palmer’s Lady Macbeth of an ex-wife (Penny Johnson Jerald) fills his head with tales of intrigue and cabals being hatched behind his back.

As a critic I have to watch everything, and I mean everything. But this year, “24” is the only show that I won’t dare miss.

• America’s favorite pop-country-bluegrass trio appears on “An Evening with the Dixie Chicks” (7 p.m., NBC). Singer Natalie Maines and sisters Emily Robison and Martie Maguire perform hits from their new album “Home,” as well as numbers from their earlier multiplatinum efforts “Fly” and “Wide Open Spaces.” Taped over two nights during the Dixie Chicks’ sold-out August appearances at the Kodak Theater in Los Angeles, “Evening” marks the group’s first network television appearance in two years.
• Patrick Stewart is host for a four night, 16-hour “Star Trek: The Next Generation” marathon beginning with the acclaimed episode “Hide and Q” (7 p.m., TNN). Stewart, who played Captain Jean-Luc Picard during the series’ seven-year run, will introduce each episode and offer details about its particular villain. And this being commercial television, he will also do his share to promote the upcoming “Star Trek” feature film, “Nemesis.” May the hype be with you.
• Two opinionated style experts help shoppers avoid becoming fashion victims on the new series “What Not to Wear” (9 p.m., BBC America). Every week, hosts Trinny Woodall and Susannah Constantine offer brutally honest opinions to a new contestant who gets a $3,000 budget to revamp her wardrobe. The results are as hilarious as they are enlightening. An American version of “What Not to Wear” will debut in March on TLC.

Tonight’s other highlights

• Andy battles with Keith for the right to go on a business trip to Paris on “Andy Richter Controls the Universe” (7:30 p.m., Fox). Note: “Andy” replaces “Grounded for Life” for the next two weeks. That series will move to the WB network early next year.
• Nick’s pregnant teen client wants to auction her baby over the Internet on “The Guardian” (8 p.m., CBS).
• A child’s abuse allegations may have been fabricated on “Judging Amy” (9 p.m., CBS).
• Andy helps Clark’s dad through a tough patch on “NYPD Blue” (9 p.m., ABC).

Series notes

An alleged deserter cites discrimination on “JAG” (7 p.m., CBS) : Kelso and Hyde brawl over Jackie on “That ’70s Show” (7 p.m., Fox) : Cate performs a solo on “8 Simple Rules” (7 p.m., ABC): Willow feels abandoned on “Buffy the Vampire Slayer” (7 p.m., UPN) : Grandma (Marion Ross from “Happy Days”) returns with news on “Gilmore Girls” (7 p.m., WB) : A neighborhood spat almost ruins Christmas on “According to Jim” (7:30 p.m., ABC).

Niles and Frasier bicker about Christmas dinner on “Frasier” (8 p.m., NBC) : A Christmas blizzard on “Life with Bonnie” (8 p.m., ABC) : Clark’s pals discover the mothership on “Smallville” (8 p.m., WB) : The holidays inspire reconciliation on “Hidden Hills” (8:30 p.m., NBC) : Office-party madness on “Less Than Perfect” (8:30 p.m., ABC) : Nikki helps Oglevee keep his job on “The Parkers” (8:30 p.m., UPN).