Daniela Ruah

Tuesday's NCIS: Los Angeles may prove once and for all just how much agents Kensi Blye and Marty Deeks really care about each other.

When a secure facility housing sensitive materials on a Marine base is compromised, Kensi (Daniela Ruah) must go undercover to get close to Stanley King (guest star Victor Webster), a world-class thief suspected of several high-end heists. Kensi has to gain King's trust by any means necessary, which isn't good news for Kensi's partner Deeks (Eric Christian Olsen).

NCIS: Los Angeles exclusive: Will Victor Webster come between Kensi and Deeks?

"Kensi and [Stanley] definitely get along," Ruah says with a sly laugh. Now whether that's for her to get closer or because she thinks he's cool, the audience will have to figure out. But there's definitely a little flirtation going on, and I think Deeks gets a little jealous."

But Ruah also says it's a safety issue. "This big-time robber seems to eliminate every partner he's ever worked with, so she's under some kind of risk," Ruah says. "Deeks is feeling really protective. It's not just the fact that they might like each other. It's also the fact that, above all, they're also partners and their job revolves around protecting each other. He has my back, I have his and that's what we do.  It's a great bonding episode for Kensi and Deeks."

Ruah says the fact that Kensi has allowed Deeks to get as close as he already has is telling. As a teenager, she lost her father. Last season, her former partner Dom (Adam Jamal Craig) was kidnapped and eventually killed, and earlier this year it was revealed that her former fiancé suffered from post-traumatic stress disorder and disappeared.

Check out photos of the NCIS: Los Angeles cast

"Kensi has a background of having lost every man in her life. She has this huge fear of losing someone else," Ruah says. "She has these walls up and I think very slowly she's letting them go down with Deeks. If something were to happen to him, it would be completely devastating."

So can those Keeks (or Densi, depending on who you ask) 'shippers look forward to something more between the characters?

"I think Kensi tries to fight against it as much as possible, but there's definitely something there that's going to be developed," Ruah says. "You want to surprise the people who watch the show. I think we have to be careful with going too far too soon; it doesn't leave a lot of places to go."

NCIS: Los Angeles airs Tuesdays at 9/8c on CBS.