The CW network, best known for fare like “Gossip Girl,” borrows a teen franchise from another era and another network. “90210” (7 p.m., CW) debuts tonight.

For reasons of its own, the network has declined to screen the series for critics.

This could mean several things. The first thing that jumps to mind is that it’s simply too dreadful to endure critical scrutiny. Movies doomed to laughable reviews are often released this way.

On the other hand, this show – so rooted in retro-kitsch and pop-culture nostalgia – just may be review-proof.

Another, more generous take is that the two-hour debut is so filled with surprise appearances and “ooh I forgot all about her” moments that the CW didn’t want crabby critics spoiling the fun.

Here’s what we know. Jennie Garth and Shannen Doherty are back from the old cast. And so is the Peach Pit. Rob Estes (“Women’s Murder Club”) stars as a high-school principal who returns from Kansas to his “old hometown,” Beverly Hills. He’s married to Debbie (Lori Loughlin, “In Case of Emergency”).

Kelly (Garth) is now a guidance counselor. Brenda (Doherty) shows up, but in what capacity is anybody’s guess. Maybe that’s why they’ve kept this under wraps.

¢ “The Shield” (9 p.m., FX) enters its seventh season with Vic and Shane making apparent threats against each other’s families. A show so filled with backroom deals, corruption, conspiracies, infidelity and gang wars should be hard to follow, but I always find it easy to dip in and out of “The Shield” without missing a beat.

Still one of the most exciting and best-written and -acted cop dramas, “The Shield,” now entering its final season, has surely left its mark.

¢ The “Explorer” (9 p.m., National Geographic) presentation “Moment of Death” presents a fascinating discussion about when we die, what happens to our cells, organs and consciousness while we are in the process of dying and invites conversation about near-death experiences and the nature of the soul.

In addition to provocative interviews with doctors, scientists and survivors, “Death” uses clever and often beautiful graphics and animation to make its points. Informative and thoughtful, this “Explorer” can even be called profound.

¢ DVDs available today include “Faerie Tale Theatre: The Complete Series,” a hit for Showtime, produced by Shelley Duvall that ran from 1982 to 1987. The series featured an eclectic cast, and directors included both Tim Burton and Francis Ford Coppola.

Tonight’s other highlights

¢ Coverage of the Republican National Convention (5 p.m., CNN; 6 p.m., MSNBC; 7 p.m., PBS; 8:45 p.m., Fox News; 9 p.m., ABC, CBS, NBC) continues.

¢ U.S. Open Tennis (6 p.m., USA).

¢ On the two-part fourth-season finale of “House” (7 p.m. and 8 p.m., Fox), a bus accident injures dozens, including one cranky doctor.

¢ A garbled phone conversation results in a scramble to explain on the charming British romantic comedy “Gavin and Stacy” (7:40 p.m., BBC America).

¢ Urban transplants try out their new electricity-generating wind turbine on “It’s Not Easy Being Green” (8 p.m., Sundance).

¢ Truck hijacking gets the “Smash Lab” (9 p.m., Discovery) treatment.