On Tuesday night's NCIS: Los Angeles, OSP psychologist Nate Getz returned from his secret assignment, only to leave again by episode's end for ... the same unknown locale.

So where is Nate? Will he be back? Is creator Shane Brennan planning an open-ended, ongoing story arc with Peter Cambor's character like we saw last season with Agent Vaile?

"I don't think this is the last you'll see of Nate," Cambor tells TV Guide.

Nate is gone ... but for how long?

"It's kind of a big mystery," the actor says, shrouded in mystery. "If there's not a bullet in my head, I'm not gone. It's left open-ended for some reason. That adds to the mystery."

Cambor says he's been sworn to secrecy by Brennan, who first pitched the storyline to Cambor last year: "I was like, 'Oh, that's different than what I thought it was going to be.'"

"But I totally understand the reasons. It's just part of the deal."

"It's a really exciting profession in the sense that you don't know what the next day's going to bring. It can be awesome, crazy, surprising and scary, but that's part of why I signed up. In a strange way, being an NCIS agent is a microcosm for the entertainment business."

For those NCIS: LA viewers dying for answers about what Dr. Getz is up to, Cambor suggests reexamining some of Nate's body language in the most recent episode.

"In 'Borderline,' when you see Nate, he's been through something," the actor says. "He's got what the other agents have: he's got a little bit of the thousand yard stare. He's learning how to use a gun, and there's a reason for that."

So is Nate in training to become a full-fledged agent? He flirted with that idea last season, and the answer ultimately may lie with Hetty (Linda Hunt), Cambor says.

"Hetty definitely has everything to do with it," he says. "She was watching Callen [Chris O'Donnell] for a long time before he became an agent. She pulls the strings when they need to be pulled, and she knows when people are ready."

Wherever Nate's headed - Callen's hint suggested Iraq or Afghanistan - look for him to be there a while. Cambor's status on the show has been changed from series regular to special guest star, ensuring viewers won't see him every week.

Cambor promises even greater changes in his character, though.

"Nate is going to continue to change and evolve, and it's going to be a long road between here and what happens to him. I'm really excited about how this all played out."

Where do you think Nate is, and how will it change him? Will you miss him on NCIS: Los Angeles in the meantime? How are you liking the series so far?

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.