Dissecting CSI's Success Story

After six seasons and a pair of spin-offs, "CSI" remains a true original and a ratings powerhouse. In the latest ratings report, "CSI" was No. 1 with 29.5 million viewers. The Early Show co-anchor Julie Chen recently spoke with the cast on the set of the show's autopsy room, trying to dissect the elements that keep "CSI" on top.

What does season six mean?

"It means that it's kind of hard to believe how quickly time goes by. And that this show is still No. 1 is astounding," says Marg Helgenberger, who plays Catherine Willows.

Paul Guilfoyle, who plays Capt. Jim Brass, jokes that he hopes it means more money. "I'm looking for double figures," he says. "I have a little daughter who was born during the pilot. I can kind of time it according to her, how she's growing up. And she's growing up!"

The show is growing up, too. In true Las Vegas fashion, the "CSI" cast and crew always seem to be "upping the ante," dramatically speaking. Last week, there was a police chase that would have been at home in any big-screen action film. And Thursday night, the aftermath of that chase becomes one of the most meticulous crime scene re-creations in "CSI" history.

"I don't personally, necessarily feel like we have to outdo each other every season," Helgenberger says. "I think that from an acting point of view, I certainly like to try to have this character continue to evolve."

If there's a theme to the way "CSI's" characters are evolving, it might have something to do with "thwarted romance."

One of the new things in this season with Catherine Willows is that Warrick Brown is married.

"Not that I wasn't professional, but I think that there always was a little spring in my step whenever I was having to solve a crime with Warrick Brown," Helgenberger says with a laugh. "Who knows where that's going to go? But, I think that it's not the end of it, there's still an act two, three, four, yet to come."

In Thursday night's episode, the sexual tension also continues between Sara Sidle (Jorja Fox) and Gil Grissom (William Peterson).

"I don't know if I'd throw him out of my bed," Fox says. "But I'm certainly not chasing him anymore. I think Sara's done with sort of actively trying to pursue Grissom. But, I still think that the window is open if he came to her in several episodes and said that he wanted to start something. I think she'd, she'd certainly not say no."

Last season couldn't have been more traumatic for George Eads' character, Nick Stokes. He almost died after being buried alive.

"For me, it's becoming clearer, as the season goes on, how he's changed," Eads says about his character. "But the evolution, the maturity of a man, I think, is measured in how he handles himself in adversity. I think he has a sense of calm about him."

And perhaps the outward manifestation of his maturity is the moustache.

"I simply, kind of, didn't shave my upper lip the couple of sessions," he says. "And then I just didn't realize so many people were paying attention. If it was up to me, I'd keep it. But it's not. And there are reasons that Nick grew it that are reasons other than why I did. But I'm going to leave that up to the fans to think for themselves what those possibilities would be. I know why."

Chen tried to pry the information out of Eads but his lips were sealed.

Friday, The Early Show goes behind the scenes with Eads. He tells what it was like, as the real-life son of a lawman, to investigate a huge police shootout.

"CSI" airs Thursday at 9 p.m. Eastern and Pacific, 8 p.m. Central time on CBS.