It's her first hangover. This is a milestone.

So, it wasn't a dream.

Castle: If we got murdered right now, I'd feel so ripped off.
Beckett: Yeah, me too!
Castle: At least we have last night. We should have done that four years ago.

Castle: Beckett, what do you want?
Beckett: You.

Every morning I bring you a cup of coffee, just so I can see a smile on your face. Because I think you are the most remarkable, maddening, challenging, frustrating, person I've ever met. And I love you Kate, and if that means anything to you, if you care about me at all, just don't do this.

Four years, I've been right here. For years. Waiting for you to open your eyes and see that I'm right here!

Beckett: How the hell could you do this?
Castle: Because I love you. But you already know that, don't you? You've known for about a year now.

Castle: You're not alone in this. I'm here.
Beckett: I know.

The most worthwhile things in life are often the most difficult. For example
(Phone rings, Beckett calling)
Wow, this really is a smart phone.

Either this is the most boring dream I've ever had or you can't sleep either.

Castle: When a life altering moment occurs, people remember.
Beckett: Maybe it's too big to deal with, maybe he can't face it yet.

Beckett: He's a human killer with a human motive.
Castle: He's a zombie killer with a zombie motive. Eating brains.

Castle Quotes

Beckett: Wait, there's a sex scene in the book? Between us?
Castle: There's a sex scene between Nikki Heat and the roguishly handsome reporter who's helping her.
Beckett: Oh, good. So he's nothing like you.

So how did she take it, us being together?

Beckett