The boss is back

Just when he thought he was out, they pull him back in! Gil Grissom (William Petersen) went all the way to a Massachusetts college to take a break from the grind of life in the CSI lab. Now that he's returned from his hiatus, however, it seems his job is about to get even tougher. Not only did his replacement, Mike Keppler (Liev Schreiber), create some chaos in Grissom's lab, the serial killer who has been taunting him by delivering miniature replicas of crime scenes has another surprise in store. And, perhaps most important for CSI fans, Grissom's office romance has hit a make-or-break point.

"Grissom has a greater understanding of his feelings for Sara (Jorja Fox) when he returns. He's so excited to see her but she's less excited to see him," explains executive producer Carol Mendelsohn. "[In part because] she spent the day in a landfill. But later we're going to see the two of them in Grissom's apartment."

Viewers have already seen Grissom write a letter to Sara, apparently expressing his feelings for her, but he never mailed it. Eventually, he'll give it to her and also come clean about the cocoon he sent her while he was away. Mendelsohn hints that it is "symbolic of their relationship," adding that there will be a payoff for fans when Grissom tells Sara, "When it hatches, you'll be pleasantly surprised."

Another surprise will be less pleasant when he goes through the stack of mail on his desk and discovers another miniature crime scene from the mystery killer. This time, though, he won't know whether the miniature is a replica of a crime already committed - or about to be committed.

"If it's the latter," Mendelsohn says, "will the CSIs be able to stop it in time?" CSI diehards take note: "There's already been a hint about the identity of the killer, a small clue with others to follow," she promises. "You just have to look closely as the hunt continues throughout this season." Here, Petersen weighs in about what's coming up - and where he's been.

Why did you decide to take this sabbatical from CSI?

A friend of mine for many years, Curt Columbus, who is artistic director of Trinity Rep Company in Providence, Rhode Island, sent me a script last year. I hadn't been taking submissions for anything while doing CSI. I might not have looked at it if it hadn't come from him, but I was sick laying in bed one day and I read it. I told my wife after I read it, "I have to do this play. It really moved me."

What was the play?

It's called Dublin Carol and it's about an Irish alcoholic, John Plunkett, working in a funeral home in Dublin on Christmas Eve. It's a very dark Christmas play but full of humor and redemption in that Irish way. I became completely enamored of this character. I knew it would be a huge challenge but I thought to myself, "This is why I'm an actor, for these kind of pieces."

How did it challenge you?

Plunkett is such a completely different character from Grissom. The great thing about this was I was playing an Irishman with a big brogue, very specific in Dublin. Plus he has to get drunk throughout the course of the show. Just in the technique of creating this character, traces of Grissom disappeared quickly.

It's tough to imagine Grissom with an Irish accent. Did it take long to get Plunkett's down?

On stage, I could do it well enough to think we were somewhere in Dublin. During previews, I met a guy in a store who was from Dublin, a salesman selling Irish jewelry. He came to the play and we went out afterward. He loved it. Except that I was mispronouncing one town's name. I thought that was funny. I guess everything else was OK.

What prompted you to want to go back to the stage?

I had the feeling that if I didn't get back on stage, I wouldn't want to go back. It's happened to a lot of actors where the further away from the theater you get, the more terrified of it you become.

Did you have any stage fright?

I had panic attacks during rehearsal. There were times when I really thought I wasn't going to be able to do it. But I talked to Amy Morton, our director, who I've worked with on and off for 15 years. She was able to allay all that, so we got through it with no problem.

Grissom's farewell was pretty unsentimental. Was it tough for you to leave CSI for a while?

Change is hard for anybody at any time. As hard as it was for the characters, it was also hard for the actors. You don't know what will happen when you leave or if it's going to be a good or bad thing or how the other people will handle it. But we shaped Grissom a little differently to show the impact on him from all of these cases. So it was an opportunity to deepen my character.

Do you think that, in a way, your leaving for a while may have helped CSI?

Yeah, it gave us the opportunity to do something different and bring somebody else in, like Liev Schreiber, and to allow a different dynamic to happen. It's good for everybody, especially in the seventh year, to have something like this happen.

Do you worry about being typecast as Grissom?

You play your character and live with him so many hours a week, you're more him than you are you. I think you can find yourself on one of these shows for a long period of time and think that all you'll ever be able to do is that character. Certainly people think of you that way. People still think of Ted Danson as Sam Malone after how many years since Cheers ended? It's always a danger.

What did you bring back from the play experience?

I certainly feel better in that I see I still have an acting life ahead of me. And I brought back some ideas for my character and Jorja's character and that relationship wouldn't have come into play in the same way had we not had that scene [when I left]. So it ends up working out for everyone.

That relationship is the hot topic for CSI fans. What's the deal? Are they a couple?

We're trying to honor the fans' devotion to it by keeping it as cool as we can. We pared it down to a simple thing for that final scene before Grissom left. We have to be a little careful. Which is why we've kept it as a background thing that may or may not be happening.

Now that you're back, what are the odds that some of your CBS peers will be asking for a break?

[Laughs] Gary Sinise [CSI: :NY] and Anthony LaPaglia [Without a Trace] came up to me and said, "How'd you pull this off? How'd you get off in the middle of a season to go do a play?" I said, "Talk to [CBS head Leslie] Moonves. I'm not telling you my secret!"