Richard Castle: You know, I got- gotta say, when I volunteered to take Cosmo, I-I thought I was doing it for his benefit. But... I realized I was doing it more for mine. I... When Alexis was little, Meredith really wasn't around. So, I-I did it all on my own. And... when yo-you said you weren't a baby person...
Kate Beckett: Okay, okay, I get it. You were thinking that...
Richard Castle: Yeah.
Kate Beckett: Okay, well, I'll tell you what. When the time comes... there's no way I'm gonna let you take care of our baby on your own.