As we first talked about last week, a longtime friend and mentor of Ziva’s, played by Karina Lombard (Rescue Me, The L Word), becomes involved in a case being worked on by the team on NCIS.

What's the premise for her arrival next month?

“We established in the [Season 9] opener that she has this friend who she was going to talk to and see,” says executive producer and show-runner Gary Glasberg. “In this episode, we’re actually going to meet this woman, who is a friend of Ziva’s who shares a bit of big sister relationship with her.”

The April episode sends the team to Colombia to investigate the case of a missing Navy chaplain.

“She participates with us and helps us figure it out. Along the way, you get an understanding of the relationship [between Ziva and her friend],” he said, teasing that it plays into a much bigger picture.

All this, Glasberg tells Entertainment Weekly, is just a piece of the character-centric puzzle they’re putting together that will come into play heavily in the ninth season finale this May.

“[Ziva] is realizing that she’s made decisions along the way. She has to decide how important a relationship is to her and what she really wants from her life too,” he says.

“It’s nice to be nine and a half seasons into a show and feel like the characters are still figuring out who they are. I feel like there’s a long way to go. It is realistic.”

NCIS was just renewed for Season 10 yesterday by CBS.

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