This year’s missing-in-action series run the gamut from sorely missed to barely remembered.

I’ve received more than a few missives from concerned fans of “The Unit.” While CBS was quick to announce which shows would return from the strike with new episodes and which would return next fall, the fate of this military drama remains in doubt and will probably be known next month, when the network announces its lineup for 2008-2009.

The network had scheduled repeats of “The Unit” to return tonight but dropped them at the last minute in favor of a “CSI” (9 p.m., CBS) repeat instead. That’s not an encouraging sign.

Formerly seen on Sunday nights, “Shark” (8 p.m., CBS) was scheduled to return with new episodes starting tonight but was furtively rushed onto the schedule last Tuesday, too late to be mentioned in this column. Paula Marshall (“Nip/Tuck”) joins “Shark” in a recurring role as a fellow prosecutor working with Sebastian.

I have to admit that it’s been a while since I gave any thought to the police drama “Women’s Murder Club” (9 p.m., ABC). Luckily for me, I can consult my old columns and find the one where I called its characters “a self-possessed and humorless bunch” who “discuss their sex lives in the same tone of voice that they use when examining a corpse in a morgue.” Oh, that show.

“Murder” will bump “Boston Legal” to Wednesday nights, starting tomorrow. That moves “Men in Trees” out of the schedule until it returns May 28.

¢ The return of “Shark” and “Club” runs up against a special episode of “Law & Order: Special Victims Unit” (9 p.m., NBC), guest starring Robin Williams as an engineer driven to extreme measures after a personal tragedy. No stranger to TV comedy specials or talk shows, the Oscar-winning Williams (“Good Will Hunting”) has made relatively few appearances as a guest star on an established TV drama.

¢ The documentary “Nanking” (6 p.m., Cinemax) recalls the 1937 Japanese invasion of China and the atrocious treatment of civilians at the hands of Japanese soldiers. “Nanking” combines archival news footage from the period and dramatic readings from the diaries and letters of Western doctors, missionaries and businessmen who remained behind to help create a safe haven for frightened civilians. Actors John Getz, Woody Harrelson, Mariel Hemingway and Jurgen Prochnow provide the voices of these witnesses.

Tonight’s other highlights

¢ Neil Diamond mentors the top five on “American Idol” (7 p.m., Fox). I can’t wait to hear someone sing the lyrics “Not even the chair …”

¢ Naturalists risk venom and worse as they try to save endangered critters on the new series “Raw Nature” (7 p.m., Animal Planet).

¢ A question of endurance on “Deadliest Catch” (8 p.m., Discovery).

¢ The USS Nimitz arrives in the Persian Gulf on “Carrier” (8 p.m., PBS, check local listings).

¢ Dahlia and Wayne sense the distance between them on “The Riches” (9 p.m., FX).

¢ “Secret Lives of Women” (9 p.m., WE) looks at life inside a polygamy cult.

¢ “Costas NOW” (9 p.m., HBO) offers a live discussion of the effect of blogs on sports journalism.