By spring 2007, the CBS drama "NCIS" looked to have run out of luck.
The show, about a team of special agents who investigate Navy crimes, had become a stalwart of the CBS lineup, even though it never attracted the media buzz enjoyed by many far less popular shows. But a poisonous rift with star Mark Harmon led to the sudden and unceremonious departure of co-creator Don Bellisario, who happens to be one of the most successful producers in TV history (his credits include "Magnum, P.I." and "Quantum Leap"). For a series that was then winding up its fourth season, such a development seemed destined to hasten a creative and ratings decline.
Miraculously, that didn't happen. "NCIS" has come back stronger and on Tuesday reached its largest audience ever, with 18.8 million total viewers, according to Nielsen Media Research. This season, only "CSI: Crime Scene Investigation" and "Dancing With the Stars" have bigger audiences.
Although most hits begin to fade by their sixth season, "NCIS" is seeing new growth -- and doing so amid a very tough market for network series in general. "We've had changes in front of the camera, behind the camera," Harmon told me in a phone interview last week. "And if you look at the result, I think in all cases we've gotten better."
If the producers could figure out a way to bottle their secrets and hawk them on studio lots, they could probably retire now and maybe fund their kids' retirements too. But "NCIS" is one of those go-figure success stories. All sorts of theories -- we'll get to them in a minute -- profess to explain why the show has kept growing.
Yet what seems maybe more intriguing are the counter-arguments, all the reasons "NCIS" shouldn't work as well it does.
Which are: The media try very hard to ignore the show. Producers realize it doesn't perform as well in New York and Los Angeles as it does in smaller markets, perhaps because the series started as a spinoff of "JAG," a popular CBS military crime drama (and Bellisario creation) that some critics found jingoistic. Harmon and the producers insist "NCIS" isn't just a procedural, but the crime-solving element is still at the heart of every episode, and network TV is drowning in crime shows. "NCIS" has seen a parade of cast changes, moreover, including abrupt exits by costars Sasha Alexander (whose character was felled by a sniper's bullet at the end of Season 2) and Lauren Holly (dispatched in a gun battle in the fifth-season finale).
And then there's the competition. Between January and May, "NCIS" airs opposite Fox's "American Idol," the No. 1 show on television. That type of scheduling could give any drama a ready excuse for failure.
But looked at more closely, "NCIS' " rise becomes easier to understand. For one thing, the series has bucked TV's trend toward serialized storytelling, which, though popular with hard-core fans and many critics, requires more dedication from viewers and has almost certainly tamped down ratings for many shows.
"NCIS" "probably has not lost many of its core viewers over time," Steve Sternberg, an executive vice president at New York-based ad firm Magna, wrote in an e-mail. "There is a small central cast and close-ended story lines. This makes it easier for new viewers to tune in and figure out what's going on."
Also, the producers have spent more time the last two seasons filling in gaps in the characters' personal lives. One episode last month showed Harmon's special agent, Leroy Gibbs, traveling back to his hometown to meet his aging father (Ralph Waite).
"Early on, it was kind of a show that moved very fast and had quick editing and a sort of staccato pace," said executive producer Charles Johnson. "I think in the last year or two, we've slowed it down and went, 'OK, we still like to break barriers in how we edit the show and all. But we also want to try and get you to know these people a little better.' "
Added executive producer Shane Brennan: "I don't think it's a bad thing, particularly in Season 6 of a show, to reinvent the characters a little."
But certainly another key to the endurance of "NCIS" lies in what happened at the end of Season 4, when news of a feud between Harmon and Bellisario began leaking into the media. Stories said Harmon felt Bellisario's management style was chaotic and led to overly long production days.
That is not quite how Bellisario saw it. Reached at his office on the CBS lot, the veteran producer said that during fourth-season production, "I asked Mark to re-shoot a scene. He redid it exactly the same way he did it the first time and never spoke to me again." He blamed Harmon and his handlers for a "full-blown PR campaign" of anonymous leaks about allegedly bad on-set working conditions.
According to Bellisario, CBS soon told him it wanted him to quit "NCIS" and work on developing something else. To date, he hasn't developed another show, he said.