Mark Harmon was looking around his workplace approvingly.

"This is a bunch of blue-collar guys who get the work done," he says.

He was talking partly about the actors in "NCIS." Like Harmon, a former college quarterback, they bring a sensible work ethic.

And he was talking about the people they portray. The real Naval Crime Investigative Service is filled with quiet crime-solvers.

Appropriately, "NCIS" has been a quiet, under-the-radar hit.

Currently, this is the only show that prospers against "American Idol." Even when "Idol" had its top-rated audition episodes, "NCIS" finished No. 9 and No. 10 in the weekly Nielsen ratings.

Part of the show's appeal is basic crime-solving, but there's more. "People like the characters," Cote de Pablo says. "And it's multigenerational."

At one end is David McCallum, 73, an erudite Scotsman who had a popular series ("The Man From U.N.C.L.E.") 42 years ago.

At the other is de Pablo, 27. "She's been terrific for the show," says Harmon, 55.

She's a native of Chile and grew up in Miami, where her mother (Maria Olga Fernandez) has been a Spanish-language TV personality. For a time, de Pablo also hosted a Spanish-language show. Now, ironically, she plays a liaison from the Mossad, the crack Israeli unit.

"Once, I had two pages (of dialog) in Hebrew," de Pablo says. "That was interesting."

The role brings a zesty, love-hate relationship with Tony DiNozzo, played by Michael Weatherly. When she was auditioning, Weatherly ad-libbed to throw her off.

"She just looked at me and said, 'Are you a maniac?' " Weatherly recalls with a grin. "Then she went right on."

He's not maniacal, but he does prefer to stay loose. After spending his first series ("Dark Angel") in a wheelchair, Weatherly, 38, bristles with physical and verbal energy.

"I ad-lib a little," he says. "I might go, 'You know what Tony is spelled backward? Y-not?' "

The show does manage to keep its balance. "We have a liberal dose of humor and strangeness," Weatherly says.