When it comes to getting geeky, ABC's crime procedural Castle doesn't mind diving in. If you're unfamiliar with the basic concept, novelist Richard Castle (played by Firefly's Nathan Fillion) follows Detective Kate Beckett (Stana Katic) on cases as research for his books. The show has featured episodes built around steampunk, comics and haunted houses, as well as a few nods to Fillion's role as Captain Mal Reynolds. Producers plan to continue both traditions with episodes before season's end.
First up, on the April 16 episode, Fillion's Firefly and Serenity co-star Adam Baldwin (Jane) will guest star. TVLine scored early images and also reported that Baldwin plays another New York City detective the novelist will follow for story inspiration. Much like his Firefly character, though, Baldwin's Ethan Slaughter turns out to be a bit rough around the edges.