After a serial killer imitates the plots of his novels, successful mystery novelist Richard "Rick" Castle receives permission from the Mayor of New York City to tag along with an NYPD homicide investigation team for research purposes.

[repeated season 3 open]
Richard Castle: [v.o] There are two kinds of folks who sit around thinking about how to kill people: psychopaths and mystery writers. I'm the kind that pays better. Who am I?
Richard Castle: I'm Rick Castle.
Richard Castle: Castle.
Richard Castle: Castle.
Richard Castle: I really am ruggedly handsome, aren't I?
Richard Castle: [v.o] Every writer needs inspiration, and I found mine.
Kate Beckett: I'm Detective Kate Beckett.
Kate Beckett: Beckett.
Ilya: Aah!
Richard Castle: Beckett?
Kate Beckett: [restraining suspect] Could you get some backup, please?
Richard Castle: [v.o] And thanks to my friendship with the Mayor, I get to be on her case.
Kate Beckett: [caught searching Castle's book in a bathroom stall by Castle] Oh!
Richard Castle: Do I look like a killer to you?
Kate Beckett: Yes; you kill my patience.
Richard Castle: [v.o] And together we catch killers.
Kate Beckett: I *hate* this case.
Richard Castle: I know! Isn't it great?
[repeated season 2 episode open]
Richard Castle: [v.o] There are two kinds of folks who sit around thinking about how to kill people: psychopaths and mystery writers. I'm the kind that pays better. Who am I?
Richard Castle: I'm Rick Castle.
Richard Castle: Castle.
Richard Castle: Castle.
Richard Castle: I really am ruggedly handsome, aren't I?
Richard Castle: [v.o] Every writer needs inspiration, and I found mine.
Kate Beckett: Detective Kate Beckett.
Kate Beckett: Beckett.
Kate Beckett: Beckett.
Kate Beckett: Nikki Heat?
Martha Rodgers: The character he's basing on you.
Richard Castle: [v.o] And thanks to my friendship with the Mayor, I get to be on her case.
Richard Castle: I'd be happy to let you spank me.
Richard Castle: [v.o] And together we catch killers.
Richard Castle: We make a pretty good team, you know. Like Starsky and Hutch, Turner and Hooch.
Kate Beckett: You do remind me a little of Hooch.
Richard Castle: I really am ruggedly handsome, aren't I?