Back stabbing, adultery and betrayal. That is why I hate politics.

Rick Castle: I know I have occasionally theorized that a conspiracy was afoot.
Kate Beckett: Occasionally?

Kate Beckett: You texted Castle and not me?
Kevin Ryan: Well, when you have a crazy theory you don't call the voice of reason.

It happened on his watch so for Ryan it means it's all on him until he finds this guy.

Rick Castle: Checking you for bites and scratches. Just making sure you didn’t somehow get impregnated.
Kate Beckett: If you think that’s how I’d get pregnant we need to talk.

Kate Beckett: Wait, you signed up to go to Mars. When?
Rick Castle: A couple years ago.
Kate Beckett: Where was I?
Rick Castle: We were fighting.

Kate Beckett: Four adults together in one space, we're bound to step on each other's toes.
Rick Castle: Yeah, well there were a lot more toes than usual tonight.

Castle we have a murder. To solve not to commit.

Kate Beckett: Thanks for coming to get me.
Rick Castle: Always.

Rick Castle: I don't know how you did it.
Kate Beckett: What?
Rick Castle: Kept it together the two months I was missing. Two days I didn't know where you were and it nearly killed me.

She’s as shrewd and high functioning of a sociopath as he ever was.

Kate Beckett: Castle, stop chasing the mice in your head.
Rick Castle: What if they're leading me to the truth?

Castle Quotes

I can't help it if you got off by putting things in my mouth.

Beckett

He has the IQ of a squirrel.

Alexis