One of Southern California's peculiar mid-winter heat waves is keeping things toasty on this early January afternoon, so the setting isn't particularly conducive to sudden chills. But you might get one down the spine anyway if you're visiting the NCIS set, since the whole damn soundstage is spook-infested.

Darby Stanchfield is making one of her rare appearances on the series — rare because her character, Shannon Gibbs, got killed 20 years ago. Which, if you're doing the math, is more than a decade before NCIS even began. Nonetheless, she's a critical specter in the show's folklore, as the first wife Jethro Gibbs (Mark Harmon) has never gotten over. Facing him now on a diner set, with their equally deceased daughter beside her, this angelic redhead is trying to convince TV's most haunted hero that his life hasn't been so tragic. "If we hadn't died, you never would have become an agent," she says, tearfully going on to mention the lives he's saved as a direct result of his family being murdered.

George Bailey, won't you please come home? "Life Before His Eyes" is Gibbs' It's a Wonderful Life episode, in which he has a moment of mortal terror and imagines a series of alternate-reality scenarios that reveal what all the characters' lives might be like if he'd made a few different decisions along the way. That's the kind of out-there gambit that, in the wrong hands, might be as much cause for shark-jumping as tear-jerking.

But this risk would only have been attempted on an occasion as special as NCIS' 200th episode. It's ironic that the show would harp so repeatedly and poignantly on the theme of roads not taken, when this exceedingly rare numerical milestone points to just how few wrong turns NCIS has taken on the way to becoming TV's No. 1 scripted show.

Not to dissuade any newcomers from tuning in on February 7 — but, says Michael Weatherly, who plays Agent Tony DiNozzo, "It's gonna be such a reward for the fans who have watched all the episodes." Of course, NCIS can afford to do one just for the fanatics — presuming that most of the 20 million first-run viewers every week count in that category, along with however many millions more are tuning in to the seemingly nonstop cable reruns.

Expect to see dead people, like Muse Watson's Mike Franks, killed off at the end of last season, but also some longer-buried former foils. "I think they'll be surprised by seeing the face of someone like Ziva's brother Ari," says executive producer Gary Glasberg, referring to a bad guy who was escorted off this mortal coil at the beginning of Season 3.

"It's a hard thing to move characters along who exited this show by ceasing to exist," says Harmon, who's clearly happy to have his old ally Watson back on the set, and even the scheming frenemy played by Michael O'Neill, who was also offed last season. "Not to say that everybody who shows up here is somebody who died," he points out.

As John Lennon would sing, some are dead and some are living, in this otherworldly, doppelgänger-filled diner. Sean Murray is passing through the set with darker colored, differently combed hair, a tip-off that even the regulars, like McGee, are experiencing alternate realities in Gibbs' fantasia. "I love doing this sort of surreal, dream-like stuff," says Murray. "The episode is about, what if things had been done differently? What if Abby and McGee were married?" (Insert a pause here as all of NCIS fandom gasps.) 

As for "Tiva"? "In my particular reality of the 200th episode," says Cote de Pablo, who plays Ziva, "I never became an NCIS agent." That's because her predecessor (Agent Kate Todd) never got gunned down — so no need for an Israeli-import replacement. Tony does have a vague recollection of catching sight of Ziva seven years ago, "but the next time we meet is now, and I've been running different missions all over Europe, and it's old Ziva — loud and in your face and sexual. It's a great scene, just between Michael and me, with the original tension all over again. So it poses the question: Is the attraction inevitable? And it kind of is."

Was NCIS' ascent to No. 1 just as inevitable, too? It was to former Man From U.N.C.L.E. star David McCallum (Ducky). "After we'd been on the air for a while and were within the Top 15, I said, 'We're going to No. 1.' And everyone said, 'Yeah, yeah, yeah.' And now we've been No. 1 for the last three years."

Other cast members had their doubts about ever reaching Season 2. "I didn't really think NCIS was going to amount to much," admits Weatherly. When he was approached, "it seemed to me a perhaps derivative spin-off of the CSI thing. I figured, hell, we'll make a few episodes. But I did get a sense right off the bat working with Harmon that he was a cagey veteran who seemed to know the direction in which we should head, all the time."

Pauley Perrette (Abby) was unsure about taking on a military-themed show in the wake of 9/11, because of the gung-ho aggression she saw in the country at the time: "I have strong political beliefs, and there has to be a lot of thought when you're going into a military show in wartime. But I think we've been incredibly responsible with this show." Her other fear was about the series' procedural structure and the stodginess that usually comes with that. "Weatherly and I did our famous pinky-shake, where we said that no matter what, every episode, we're gonna bring the funny. And we have."

For more with the cast of NCIS, pick up this week's issue of TV Guide Magazine, on newsstands Thursday, January 19!

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