Fans of Castle may already know that he'll start season three as a murder suspect. It goes without saying he'll clear his name and will probably figure out who did it before the cops do. Still, the damage will be done: he'll have serious trust issues with Kate Bennett for years. After all, if she's eager to arrest him for anything, it's obvious he thinks he'll never be good enough for her. Any sexual fantasies he's got for her will wind up in his books. She may even arrest him for that, too.
Also, he'll be busy with a movie adaptation, Alexis dating and a serial killer Kate can't catch. They won't have any time for failing to connect romantically.
As a veteran of past romance shows where the male and female leads try to connect, but do a terrible job at it (from Cheers to Moonlighting), I suspect Castle is stuck in this track, It's not like Friends, where Ross did win Rachel after all, The Closer, where Brenda Johnson did marry her beau, or The Office's Jim and Pam.
That being said, what can we expect on Castle for the next five years?
First, I'm guessing when Kate does corner the serial killer that will taunt them all season, the killer may be about to kill her. Then Castle saves her, and she gets mad at him because he never stays in the police car after telling him to. However, Castle gets shot with a serious wound. He recovers, but she's so mad she doesn't visit him at the hospital.
The experience inspires him to write a third book where Nikki (Kate) and Jamison Rook (Castle) battle a serial killer. The only difference: Jamison is also shot, but dies. This would serve two purposes: it means a lonely life for Nikki Heat for another book or two, and it forces Castle to stop living out his sexual fantasies in his books.
The book is well-received, but fans are upset Jamison is dead. They eventually get over it when Castle explains he's just aiming the Nikki Heat series towards a new direction. He does think about a Jamison Rook prequel, but doesn't mention it.
However, a really crazy fan expresses her anger over losing Rook. She kidnaps.....Kate Bennett, thinking that Kate told Castle to kill Jamison because everyone thinks those scenes are really her and Castle. The fan demands that Kate confess this, or at least admit she loves Castle, but just can't tell him because she doesn't think it would work out. Surprisingly, Kate does just that, or just enough. Kate's rescued, and she asks Castle why he killed Jamison. He repeats the "new directions" explanation, and that is that. The fan sees this, and starts to think she kidnapped the wrong person.
So, when will Kate figure out the truth? I am guessing another obsessive fan will approach her, but only to ask Kate if Castle killed Jamison because he doesn't think he's good enough for her. Kate asks this other woman if that means it's her fault, and the other fan backs off. Still, Kate thinks she's got to confess her feelings, but never does because of another case or something.
After that, well, maybe Castle will once again save Kate when she doesn't want him to, and that finally does it. The producers should realize that if you take too long in pairing up Kate and Rick, the fans will get bored, if not upset, about it.
After all, if they want to see a pretty couple exchange banter but never have sex because they don't want to try, they can watch Bones. If Hawaii 5-0 gets much more successful against Castle, Nathan Fillion may have to rethink his comments on G4 about why Kate and Rick should never get together.
Two words, Captain....The Closer. And besides, Wash and Zoe were interesting as a well-armed married couple....
UPDATE: Just had to admit that I was right that someone wound up getting shot at the end of season three...and it was Kate. Not only that, it was Castle who said those magic words. I will not guess about what will happen next until the ComicCon panel on the show. Of course, I'll be 99 percent wrong...but what I speculated could have happened..maybe. Except I'm not part of the show's writing staff, so what do I know?