NCIS is heading into its 13th season this fall, but don't expect to see signs of fatigue from the writers' room.

"Every year that I come back after hiatus, I'm curious if this is the year when the writers are starting to feel the issues of being a 13-season show," showrunner Gary Glasberg tells "Instead, everybody came back full of ideas and energy and ready to go."

What that means for Season 13 is a renewed focus on individual story lines. "In the first dozen episodes of this season, we're really going to get into a lot of character stuff for each one of our team members. People should be prepared for a very, very active season," Glasberg promises. "We're making an aggressive attempt to get everybody out, to do some things that we haven't done before."

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Here's what's in store for the major players on NCIS this season:

We already know - spoiler alert? - that Gibbs (Mark Harmon) survives the shooting at the end of Season 12. But it will definitely have lasting effects. "People are going to be in for some really significant twists and surprises to Gibbs' return," Glasberg teases. "There are definite changes and adjustments to the Gibbs character in this near-death experience that he has. There are physical changes they'll see. There are some psychological changes. There are changes in his approach to his agenting." (And, as we'll learn in the second episode, to his wardrobe.) We'll also continue to learn more about Gibbs' past, particularly in Episode 2, when he "gets involved in a case that an old friend brings to him that sheds a bunch of light on ... things that we still don't know about," Glasberg promises.

In Gibbs' absence, Tony (Michael Weatherly) "really rises to the occasion" in tracking down the terrorist group The Calling and bringing that case to a close, Glasberg says. Could Tony's trip to Los Angeles this fall be prompted by difficulties in his home office? Gibbs' recovery causes him to butt heads with his right-hand man, Glasberg teases. "There's absolutely some conflict. There's issues that have to get worked out between team members, very specifically between Tony and Gibbs," he says. Robert Wagner will also be returning in at least one episode as Tony's father.

Amid the conflict between Tony and Gibbs, fans should be prepared to see a different side of McGee (Sean Murray). "We end up relying more on McGee and letting McGee kind of step up and be the strong agent that we know he can be," Glasberg says. On the personal front, Delilah (Margo Harshman) will be back "significantly" throughout the season.

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In addition to exploring more of Bishop's (Emily Wickersham) personal life, including "some issues that she continues to have with her husband Jake," according to Glasberg, the upcoming season finds Bishop testing the waters of an unexpected workplace romance. But don't worry - it's nothing too scandalous. "There's a fun undercover case that happens in the third episode, where McGee and Bishop play a married couple," Glasberg teases.

It's possible that we'll see some developments in Abby's (Pauley Perrette) love life this season, with Glasberg hinting that her Park Police Sergeant boyfriend, Burt (Johann Urb), may be returning. There's also an Abby-centric installment in Episode 5, when the lab comes under attack. But Glasberg is staying mum on that - except to describe the hour as "a Die Hard with Abby Sciuto story line." We just hope that Bert is involved.

That's right - Vance (Rocky Carroll) is coming back! An early episode features him and Gibbs in "kind of this Butch and Sundance relationship that gets Vance out of the office and back into the field," Glasberg says.

NCIS premieres Tuesday at 8/7c on CBS.

(Full disclosure: is owned by CBS.)