“We’re the dinosaurs,” a jovial William Petersen says as he sits alongside longtime partner in crime-solving Jorja Fox in Los Angeles. “Billy’s more like a T. rex,” she counters with a laugh. The pair are talking to TV Guide Magazine about their iconic CSI: Crime Scene Investigation characters—dispassionate forensic entomologist Gil Grissom and his wife, intrepid forensic scientist Sara Sidle—returning to the lab in CSI: Vegas, a sequel to their 2000–15 crime drama sensation.

Last seen sailing off into the sunset in the 2015 finale movie Immortality, Sara and Grissom “were my favorite parts of the original and the perfect entrée into the story we’re telling here,” says executive producer Jason Tracey. Vegas joins a franchise that has already spawned three spinoffs, CSI: Miami (2002–12), CSI: NY (2004–13) and CSI: Cyber (2015–16).

An attack on their old workplace is the catalyst that brings the happily married couple back to dry land. “Someone’s targeting the lab. A conspiracy calls into question the integrity of the work we always saw get done,” Tracey says. “Thousands of prior convictions hang in the balance.”

New faces in Vegas include boss Maxine Roby (Paula Newsome, Barry), who’s a geneticist; senior investigator Josh Folsom (Matt Lauria, Kingdom); Level 2 CSI Allie Rajan (Mandeep Dhillon); and head medical examiner Hugo (Mel Rodriguez). We’ll also see past team members David Hodges (Wallace Langham), now an expert witness, and, for two episodes, retired LVPD captain Jim Brass (Paul Guilfoyle).

First, Petersen and Fox tell us why they decided to roll the dice on CSI: Vegas.

Congratulations, first of all. How has it been revisiting Sara and Grissom?

William Petersen: Completely weird because we thought we’d put this to bed a long time ago. It’s a whole new thing and yet still the bones of the old thing.

Jorja Fox: Like Groundhog Day on some psychedelic [level].

When you first got the call about this sequel, what were your reactions?

Petersen: I was hesitant, but the idea of coming back and doing this with Jorja…

Fox: I was also hesitant—I felt like the story left Sara and Grissom in paradise together—but getting to work with William Petersen again? They had me at hello!

Petersen: It’s like riding a bike; you just get right back on. We got a tandem and we know how to do it.

What’s the state of the union for these two characters?

Fox: First of all, I love Sara and Grissom. I always will. Not to talk about the olden days too much, but even though we were together, we weren’t together. We were [secretly] married, we were divorced. Embarking on this phase, we’re going to meet them not only as a couple that’s together, but a couple that’s been living on and off a boat together for several years.

Petersen: We’re working on saving and studying fish, protecting sharks, down in South America somewhere.

Fox: We kind of pulled a Jimmy Buffet.

Petersen: We’re in Margaritaville.

What on earth could cause Sara and Grissom to ditch that for Las Vegas?

Petersen: Somebody accuses the Crime Lab of having falsified evidence, and it goes back over a long period of time.

Fox: All of the characters are tapped into [this case] for the duration of the season, and the stakes are really high. There’s loved ones involved and the safety of loved ones. And through that, we meet the new CSIs and forge those relationships.

There are weekly cases too—Sara still has CSI accreditation, and Grissom signs on as a consultant. But has the technology left these two behind?

Petersen: [Grissom walks] through the lab and [doesn’t] even understand what the machines are.

Fox: I thought it was difficult to get away with a crime in [the year] 2000. Now there’s no way to get away with murder! The science is a thrill!

Will we finally get to see some PDA this time around?

Petersen: Our attraction to each other was always based on the work. We were always in some kind of mind meld when we were working. There was nobody he would rather be in the lab with or on a crime scene with than Sara. She got it. She got him, and he eventually got her.

Fox: [Grinning] The show is going to air at 10pm, so we can be a little edgier than we were last time.

CSI: Vegas, Series Premieres Wednesday, October 6, 10/9c, CBS

This is an excerpt from TV Guide Magazine’s 2021 Fall Preview issue. For more inside scoop on the new fall TV season, pick up the issue, on newsstands Thursday, August 26.