Castle-Nathan-Fillion-Adam-Baldwin.jpgIn “Headhunters,” the Monday, April 16, episode of ABC’s “Castle,” fans of FOX’s much-loved but short-lived science-fiction series “Firefly” get to see a bit of a role reversal.

On “Firefly,” Nathan Fillion played Captain Mal Reynolds, the swashbuckling, war-hardened commander of a spaceship, and Adam Baldwin played Jayne, a mercenary member of his crew.

But on “Castle,” Fillion is Rick Castle, a New York mystery writer moonlighting as a civilian NYPD consultant, and Baldwin guest-stars on Monday as Detective Ethan Slaughter, a swaggering, two-fisted member of the gang unit.

“I just loved the dichotomy,” Baldwin tells Zap2it over fish and chips in West Los Angeles, “of being on his show with the character license to play the boss. The character was written such that Slaughter’s the boss, and I was able to walk in and go, ‘OK, it’s my scene.’ Every scene is my scene.”

Castle teams up with Slaughter on a case but soon finds that it’s a lot more dangerous than his regular gig as the unofficial partner of NYPD Detective Kate Beckett (Stana Katic), the inspiration for his fictional character Nikki Heat.

“Castle’s kind of a puppy-dog character,” says Baldwin, “but he’s still a tough guy. We put him through his paces. The difference was, on ‘Firefly,’ Jayne was always subservient. He would have this faux bravado, but he would know, in the back of his head, ‘I’d better not cross Mal, because he’ll space me.’ Not so here.

“Slaughter doesn’t care. ‘Go ahead, Castle, take a swing at me, I dare ya,’ that sort of thing.”

The situation also made it a bit easier for Fillion to provide laughs for the audience.

Castle-Adam-Baldwin-2.jpg“Comedy is a strange beast,” says Fillion, calling in from the set during filming on the “Castle” season finale. “It’s very difficult to make someone laugh, although it’s very easy to allow someone to laugh at you. It’s easy to allow people to laugh at you while you’re being bullied by a big giant of a man like Adam Baldwin.

“He’s got a mean smile. He’s obviously happy, but there’s mean behind it.”

Asked if there might be a “Firefly” reference or two scattered through the script, Fillion says, “You couldn’t stop us. We were doing stuff, going, ‘”Firefly,” is that too “Firefly”?’ Alexi [screenwriter Alexi Hawley] was kind enough to build some right into the script, and we tried to see what we could do on our own.

“Sometimes we were saying, ‘That’s a little on the nose. We can’t do that. That’s just too much.'”

Fillion not only wants to have some familiar guest characters and actors back next season — perhaps including Baldwin reprising Slaughter — he would also like to see more “Firefly” regulars on the show. In fact, if he had his way, he’d prefer to see all the other “Firefly” regulars on the show, all at once.

“I’ve been pitching an episode for ages,” Fillion says, “about an actor murdered, and he’s a former actor of a sci-fi television program. He’s the captain of a spaceship, and it turns out that everybody hated him. He’s such a jerk, and everybody in the cast of the show is suspect.

“I want to bring back the entire cast of ‘Firefly’ and have them all rail on the one guy who’s dead now. They’re glad he’s dead.”

Of course, he now can’t use Baldwin in that episode, so a different actor would have to play the Jayne-type character.

“Yeah,” says Fillion, “and the character will look like a really tough guy on TV, but in real life, he’s really effeminate.”

Regarding the possibility of some sort of a romantic resolution between will-they-or-won’t-they unrequited lovers Castle and Kate by the end of the season, Fillion says, “There is hope. there’s hope of that.”

Posted by:Kate O'Hare