Browncoats assemble! Tonight's episode of Castle, "The Final Frontier," is poised to be an action-packed hour of Firefly references galore. But that's not the only nerdtastic sci-fi aspect fans can look forward to.

According to the official show synopsis, Castle and Beckett head to a science fiction fan convention much like San Diego Comic-Con after a TV superfan named Annabelle is found dead. Their investigation leads them down a dark and twisted road lined with "egotistic celebrities, diehard costumed fans, and enough drama for two galaxies.”

At the center of this mysterious murder is a TV series called Nebula 9. The show has long been canceled unjustly, according to the show's lead actor Gabriel Winters — and Annabelle was last seen organizing a special fan experience with the cast and crew for the convention.

Much to Rick Castle's surprise (and amusement), Kate Beckett seems to know an awful lot about Nebula 9, a show that isn't really taken seriously among the serious sci-fi buffs. And thanks to this awesome sneak peek clip, we learn that she's hiding an even bigger secret underneath her perfectly polished Burberry trench — Nebula 9 cosplay gear!

"We’re about to learn that when she was at Stanford, she dressed up like this mythical character Lieutenant Chloe, who was on Nebula-9 — and there’s photographic evidence of that period of her life that, as you could imagine, entrances Castle," reveals director Jonathan Frakes in an interview with TVLine.

Although he chides Beckett for her co-ed cosplay habit  — "I like good sci-fi," he tells his detective girlfriend. "Star Trek. Battlestar. That Joss Whedon show" — he must find it a bit endearing. And sexy.

"Ohhh, wait ’til you see the last scene of the show," Frakes teased, dishing even more info to Zap2It: The last scene in my mind at the Final Frontier convention is something that will take their relationship to another level — if you'll pardon the expression, the final frontier."

Castle Season 5, Episode 6: "The Final Frontier" tonight, Monday, Nov. 5, 2012 at 10 p.m. ET on ABC.

Sources: Zap2It, TVLine


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