Kate: "You trapped me in here on purpose."
Castle: "No, I didn't. But since you brought it up, tell me: why do you feel trapped in our marriage?"
Kate: "I don't."
Castle: "Then why did you leave?"

"I don't want a divorce. I want my wife back."

Castle: "What might drive a person to murder?"
Scott Powell: "I don't know. Revenge?"
Castle: "Revenge. A man wronged, his reputation besmirched. So he strikes out in passion. Some might consider his actions justified. What else might drive a person to kill?"
Scott Powell: "Being forced to read one of your books? [the class 'oohs'] Though that's probably more of a motive for suicide."

Kate: "You went to an underground prison? Alone?"
Castle: "No. Not alone; I had Alexis with me."
Kate: "Oh, well, since you had backup. Are you kidding, Castle? Your daughter?"
Castle: "When you say it in that tone, I sound like a bad parent."

Kate: "Castle, I asked for time. Why can't you give me that?"
Castle: "Because you need me."

Dr. Barbara Lillstrom: "That man is insane. I'm innocent."
Kate Beckett: "If he says you're a suspect, then trust me, you are far from innocent."