Castle Season 5 premieres on September 24.

In anticipation of the return of one of my favorite shows, I spoke to star Seamus Dever last week about the conflict between Ryan and Esposito, what's next for Kevin and Jenny and how Castle and Beckett crossing that line has changed things for everyone...

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Will we see Esposito and Ryan forgive and forget or is it going to take some time for these two partners to get back together?
I think the stakes are pretty high as far as what the betrayal meant for Esposito. I don't consider it ever to be a betrayal. I think that the ends justify the means. The whole thing was sort of about each individual person's definition of doing the right thing. I feel like Ryan did the right thing because he was never really excited about covering up for crooked cops.

He sort of considers Montgomery to have been a crooked cop. Why should we cover for these people? What are we hiding? And Esposito, his point of view was that doing the right thing was standing up for other cops and honoring Montgomery's memory.  That was his right thing. This sort of started during the season 3 finale and it came around this time (in "Always") with Ryan deciding that doing the right thing meant saving Beckett's life. I'm not quite sure how it's going to resolve itself but there's definitely some tension for them coming back together. I think eventually we're going to see Ryan and Esposito work out their differences and figure it out.

Any chance Ryan will have to partner with someone else for a while?
No. Our show is what it is. We have very few surprises as far as outside people coming in. So, no but we have to get back to business and solve some crimes. But there's definitely some tension where they are forced to work together.

Can we expect another Ryan focused episode, like we had in "Kick the Ballistics" last year?
There's talk of it. Yeah, I hope so. I think it would be a lot of fun. It's always great to sort of explore the past of a character and there's still a lot to explore for Ryan that hasn't been revealed. So, there's talk of that. We hope it fits in there. In my dream of dreams we'd all have our nice, breakout episode where we learn a little bit more about each of the characters but that isn't always a possibility. We'll see what happens.

Have you heard anything about the 3XK killer coming back, since Ryan was very involved in that story?
I think it's going to happen again. I think he's going to reemerge but I think this time it's going to be a little more focused on Castle instead of Ryan. That little scene that they had of him being tied up and sort of threatened by 3XK is going to come around again and I think we're going to see some of that.

So far, have you had a favorite storyline on Castle?
I love the wedding storyline and getting to have my wife on the show as my girlfriend and then fiance and now my wife. That's always been a fun storyline. I think the proposal episode ("Nikki Heat") that we did where Ryan proposed to Jenny was some of the most truthful acting I've ever done on camera. I was very pleased with the way that worked out. There was a lot that you can use from real life in the work.

As far as episodes, there are always my favorites. We had a fun time at the casino episode ("Heartbreak Hotel") last year. That was just a lot of fun dressing up. It was sort of ridiculous, like we're suddenly dressed up like Elvis. I kept trying to figure out the way that Elvis pointed with his pinky and his forefinger out. I kept trying to insert that in a scene and it made it at one point where I'm gesturing that way. There's fun stuff like that. Like "Kick the Ballistics" was one of my favorite episodes.

Still one of my favorites is "The Double Down" where we got to bet against one another. That was a great one. The steam punk episode ("Punked") was a lot of fun because there was a lot of physical stuff we were suddenly doing. The stuff last year with the wedding ring. That was a lot of fun with me and Jon. Those scenes turned out pretty good. I was pleased with that. So yeah, there are lots of favorites.

It sounds like you love your job.
Yeah, it's a great place to go to work.  They give us some fun stuff and I get to work with some fun people. We show up and make it even funnier and we make ourselves laugh while we do it.  And we go, OK I think everybody's going to laugh with this.

Speaking of your wife, Julianna, fans love her character, Jenny. Will we get to see more of Mrs. Ryan this season?
I think so. Again, there's talk. We hope that all of these things we talk about at the beginning of the season come to fruition. There is talk of Jenny coming back. Is there going to be an instance of the Ryan's starting a family? There's talk of that. We'll see what comes around and how these things develop in Kevin and Jenny's life.

Now that Castle and Beckett have crossed that line and it feels as though the show is going into new territory, what's the feeling on the set? Is it excitement? Is it hesitation?
(Spoiler Alert!) First of all, we shouldn't actually take it for granted that everybody knows that they're together. They're now together and keeping it a secret from the rest of us.  We're sort of teasing out this thing of who notices what and who gets suspicious. Who finds out first and who figures it out and do they let everybody else know? Is it one of those things where we have to keep this from Gates because this means they'll definitely be split apart at this point?

It's one of those things that's sort of fun to see them do a lot of stuff where they start sharing something or having personal conversations and one of us comes up and asks what are you talking about?  And they're like, Nothing. Where are we on the case? So that's something that gets teased out. At this time I think that Esposito is a lot more suspicious than Ryan is about their lingering looks and their gestures and glances and physical contact and things like that. I'm actually really curious to find out who figures it out first.

On a personal note, I hear you had a birthday recently. Did you do anything fun?
I worked at Castle until very late. I celebrated a small little party with my dad. My dad was born two days before I was and every 11 years we have a reciprocal birthday where he turns one number and I turn the reverse number. I turned 36 and he turned 63. It's sort of a funny, weird thing that my dad had me when he was 27 and every 11 years starting when I was three we have reciprocal birthdays. So I spent it with my Dad. That's what we generally do.  I took him stained glass shopping because he's into stained glass and he bought me a bunch of tools because I'm into woodworking. He bought me a bunch of cool clamps and stuff.

Your Twitter followers (@seamusdever) have gotten to see some of your woodworking projects. Have you made anything interesting lately?
I made a great table the other day. I made some table tops out of old Bordeaux cases. They're all pine so it's a really soft wood so you can cut it pretty easily and it's light weight. I figured out that I can use six of these Bordeaux case fronts together where they have the name of the chateau.  My wife and I are into wine.  I did this cool little project where I made them look like they were made a long time ago and did a fun amber shellack and covered them with polyurethane and now they're outside on my patio. I just love working with fine detail and I guess I've always sort of been into carpentry so that's something that I've been working on in my shop.

C. Orlando was a TV Fanatic Staff Writer. Follow her on Twitter.