Melina Kanakaredes and Gary Sinise, <EM>CSI: NY</EM> Melina Kanakaredes and Gary Sinise, CSI: NY

Something remarkable happened while shooting this season's opening episode of CBS' CSI: NY (Wednesdays at 10 pm/ET). Instead of the usual nose-holding over the rotting corpse du jour, the actors huddling around the playback monitors were doing puppy-dog head tilts and whispering, "Awww."

"It was so sweet," says Melina Kanakaredes, who plays the normally tough-talking detective Stella Bonasera. "I mean, Mac and Peyton are adorable together."

Sweet? Adorable? Is this CSI: NY or 7th Heaven? After two seasons of by-the-book forensic gumshoeing, the crime drama's focus has suddenly shifted to topics that are decidedly more… cuddly. And it's not just the actors who are cooing. New, more personal story lines, including the burgeoning affair between hard-bitten Manhattan investigator Mac Taylor (Gary Sinise) and Dr. Peyton Driscoll (Claire Forlani), a British medical examiner, are helping push CSI: NY into ratings territory normally dominated by the original CSI and CSI: Miami.

"In terms of the franchise, CSI: NY was definitely the New Coke for a while, but now everybody's onto it," says Anthony E. Zuiker, an executive producer of unimaginable fortune for having created all three CSIs. Since Law & Order moved to Fridays, roughly 16.8 million viewers are now tuning in to CSI: NY weekly, making it the No. 5 scripted series on TV. That's up from No. 14 during the first two seasons. "I've been traveling through a lot of airports lately," says Sinise, "and I've never gotten so much, 'Hey, man, great show' or 'Love ya, Mac.' Something definitely shifted."

The changes began emerging last season, after CBS chief Leslie Moonves asked producers to add more light and color to the show's shadowy palette. "My family likes to say the show started getting more successful the minute people could see my green eyes," Kanakaredes says. The introduction of a new, multimillion-dollar lab set probably also had an impact.

And it helped that CSI: NY is moving beyond the procedural. As last season drew to a close, Kanakaredes' character was taken captive by her stalker boyfriend, Frankie Mala (Ed Quinn), and she killed him in self-defense. It's an event that "exposed the show's emotional heart," Zuiker says. Adds Kanakaredes, "We all knew the franchise was successful because of the mystery element and the sexy science, but it wasn't until we started bringing down the walls around our characters that the heat really kicked in."

And she's not the only one feeling it. Mac and Peyton might soon have to take a number for the laboratory broom closet. Street-smart investigator Danny Messer (Carmine Giovinazzo) has developed an unrequited crush this season on his ranch-bred colleague, Lindsay Monroe (Anna Belknap). "It's one of these flirting-despite-yourself relationships," says Belknap, who explains that the story line actually developed behind the scenes last season, when she and Giovinazzo mistakenly bumped into each other in the drug-processing lab. "We awkwardly turned around and said, 'Oh, oh, sorry, sorry,' and everyone said, 'Ooo, that's so great! Let's play up that chemistry.'"

In real life, Belknap is married to actor Eric Siegel and pregnant with her first child, due in January. Initially, the writers talked about incorporating the pregnancy into the show, but as Belknap points out, "People who do this job for real can't work around so many chemicals when they're pregnant." The actress says that she intends to return to the show after a brief maternity leave. One plan has her character leaving New York to visit her native Montana, though as Belknap says, "I don't know how anyone can go to Montana with things getting so good in New York."

Inside Sinise's trailer on location in downtown L.A., the actor grabs his last two cans of Red Bull. "It's been that kinda week," he says with a laugh, opening one and handing the other to his guest. Even though he squeezed in an afternoon nap today, Sinise's trademark tired eyes tell the real story.

The demands can be grueling on a weekly drama like CSI: NY, with its movie-style production values and 16-hour-plus shooting days. The show's actors routinely work through the night to get a scene just right. "We sing show tunes to stay awake," says Kanakaredes, "and I keep threatening to pitch an all-musical CSI: NY. 'I've got the hair! He's got the NY fiber! You've got the evi-de-e-ence!'"

Sinise probably wouldn't mind. He travels the world playing benefit concerts with his rock band, and recently jammed at a crew party. "I can't really do theater anymore, so this is my fix," says the actor, who cofounded the legendary Steppenwolf Theatre Company in Chicago. He also frequently brings his kids (two girls and a boy with actress wife, Moira) to the set, as does Kanakaredes, who has two girls with husband Peter Constantinades, a chef. Says Kanakaredes, "Some guy's head is half blown off, and my daughter Zoe is selling Girl Scout cookies."

Hill Harper could use the sugar rush: He uses his study habits from Harvard Law School to play medical examiner Dr. Sheldon Hawkes. "Hill goes on the Internet for hours when he gets new scripts so he knows the facts behind the medical dialogue," Zuiker explains. Harper recently visited a police "body farm" for two days "to watch corpses decomposing and liquefying," Zuiker adds. "It's definitely nicer working with fake dead bodies," Harper says.

Then again, CSI: NY isn't just for stiffs anymore. Zuiker hopes Christina Aguilera will guest-star around the time of the Grammy Awards in February. He says the singer won't play herself in the episode, which will probably deal with domestic violence. Also coming up: Criss Angel of A&E's Mindfreak will perform three never-before-seen illusions.

As for the regular cast: "We'll be deepening every character's backstory," Zuiker says. Hawkes will explore his angst over having lost two patients in his previous career as a heart surgeon. Stella will freak when she comes into contact with contaminated blood — but she'll also contemplate new love relationships. Kanakaredes says, "My joke is that Mac will probably get ahold of whatever guy Stella lands next and say, 'Hey, be careful. She killed the last one.'" Meanwhile, Lindsay's standoffishness with Danny will make sense after it's revealed that she experienced a trauma in her past that keeps her from trusting.

And what about that "adorable" couple everybody loves to coo about? "The audience response to Mac and Peyton's relationship has been tremendous, so we'll see where it goes," Sinise says. In other words, it's only a matter of time before the Tiffany engagement ring and the Central Park wedding, right? "Don't count on it," Zuiker says. "Just because we're taking these characters home doesn't mean we're in the soap-opera biz."

Also in the Dec. 4 issue of TV Guide: Five things you don't know about CSI: NY, plus a look at the cause most dear to series star Gary Sinise's heart.

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