John Huertas, Kelly Hu

Castle's Jon Huertas has been thrilled with the opportunity to take a closer look at his character, Detective Javier Esposito, during the ABC drama's fifth season.

Following a Christmas episode that highlighted Esposito's loneliness now that Detective Ryan (Seamus Dever) is married and his booty calls with Lanie (Tamala Jones) have become less frequent, last week's episode featured Esposito taking special interest in an at-risk youth and revealing his character's own troubled upbringing.

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"I thought it was an interesting story line," Huertas tells TVGuide.com. "[It was] something I felt I could relate to. It was nice to be able to show that sometimes someone can come into someone's life and be that instrument of guidance for them to do better. On our show, it's always the male-female type of relationship. So I was really excited that it wasn't about two people falling in love or playing with the idea of love."

That's not to say the issue of Esposito's love life won't be explored. In fact, Monday's episode (10/9c, ABC) finds Esposito taking more than a professional interest in a suspect. Kelly Hu plays Scarlet Jones, the bodyguard of a Joe Francis-like adult entertainment mogul. When he ends up dead, all eyes are on Scarlet, who makes an unusual (perhaps intentional?) mistake for someone running a security detail.

"Being a former Special Forces military guy and a cop that's probably been on several executive protection details through the NYPD, Esposito sees a flaw in in her technique," Huertas says. "Is that actually a mental flaw or is that something that she set up? So we investigate it in that way. At the same time, she's pretty badass, so that's something that Esposito is attracted to. He wants a girl he can wrestle with."

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Adds Hu: "He does criticize her at first, and she, of course, doesn't take too well to that. But sometimes the person you butt heads with the most is the person you're attracted to the most."

So is there some connection between Esposito's recent actions and this sudden attraction to a new flame? "There's a hole in him, and there's something there that Esposito longs for," Huertas says of his character. "[Maybe] it has to do with family, with a relationship, maybe with father issues. That's from my own personal issues, so I would love to explore that. For me, sometimes playing Esposito is like therapy. I get to air my own self out."

But Hu's not certain her character's fling with Esposito is necessarily that deep. "I think he's interested in sleeping with her — it's that simple," she says with a laugh. "I think he makes it pretty clear. It becomes more complicated, and the date doesn't go as planned. Just when you think it's going really well for him, it doesn't."

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And how does Lanie figure into all of this? Though Huertas says Esposito mostly keeps Lanie in the dark about his new flirtation, Hu, who says she thinks her character could easily return, is prepared for fan reaction. "I know there are fans out there who are really rooting for the Lanie character to get together with Esposito," she says. "So I might ruffle some feathers there. I might get a little bit of hate mail.  Bring it on!"

Castle airs Mondays at 10/9c on ABC. Check out a sneak peek of Monday's episode below:

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