Stana Katic is leaving 'Castle'
IN PHOTO: Stana Katic poses with the award she won for favorite dramatic TV actress for her role in the series "Castle" at the 2014 People's Choice Awards in Los Angeles, California January 8, 2014. REUTERS/Kevork Djansezian

"Castle" Season 6, Episode 12 spoilers reveal James Brolin is reprising his role as Rick Castle's (Nathan Fillion) mysterious father. The People's Choice Awards 2014 winner for "Favourite TV Crime Drama" airs a new episode this week, titled, "Deep Cover." Meanwhile, Stana Katic thanks fans on Twitter, saying she's "blown away" by the public's thumbs-up.

Spoiler alert: This feature contains spoilers on Castle 6x12. Watch the sneak preview to see James Brolin come face to face with Martha (Susan Sullivan). "Deep Cover," this week's new episode on ABC, airs Monday, Jan. 13.

A lot of things are set to unfold in ABC's Castle Season 6. The wedding is likely to happen in the finale, but just as likely, there will be more crime cases to solve.

In an interview with TV Guide, James Brolin ponders the essence of Rick's dad. It seems he dished some creative contribution to Castle Season 6, Episode 12, Deep Cover. Brolin says Jackson Hunt is like Dexter Morgan. (Yes, the husband of American diva Barbra Streisand watched the Showtime series.)

"I feel very clear about (Castle's father) not being your ideal person in life. He's saved a lot of lives and done the world a lot of good - because he loves to kill. I like the simile to Dexter," Brolin told William Keck. Watch the sneak preview to see him fire a shot, seemingly right in front of Rick Castle.

The sneak preview video below and the spoiler reports hint this new episode will be more than just interesting. In "Deep Cover," the character played by James Brolin gets darker. He comes face to face with Martha. When he's not wounded and covered in blood, he is hitting on Stana Katic's Kate Beckett. And of course, Nathan has to tell Dad he's marrying the gorgeous New York City Police detective.

WATCH: Castle Season 6, Episode 12, 'Deep Cover' Sneak Preview on YouTube

Castle Season 6 has started the year 2014 in high spirits. On TV, Kevin Ryan (Seamus Dever) is now a dad to a healthy baby girl. In real life, Stana Katic has won the Favorite Dramatic TV Actress award on PCA 2014. The show itself won in its category. Here is Stana's reaction on Twitter. (Follow this link for Stana Katic's PCA Acceptance Speech.)

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