Castle Episode 5.06 The Final Frontier

There are enough inside jokes to fill a space cruiser in this sci-fi-centric episode of Castle. We'll make mention of a few of them, but feel free to detail your favorite moments from this particular space case in the comments section below. There's an armada of sci-fi-friendly guest stars being directed by Commander Riker himself-Jonathan Frakes. Look for his cameo as Castle's "#1 fan." Told ya there were a lot of inside jokes. You can take our Sci-Fi Fun Quiz focusing on the spacey connections of the Castle cast and the guest stars. But for now, please join us as we boldly go where no mystery writer and his muse have gone before-to a deadly sci-fi convention.

Beckett pulls Castle away from his book signing for Storm Season to investigate a murder at SuperNovaCon. The killing of Annabelle Collins occurred on the bridge of a spaceship used for a fan experience adventure for the show Nebula-9. Castle was never a fan. He likes good sci-fi products like Star Trek, Battlestar Galactica and that old Josh Whedon show. We're guessing he's talking about Firefly, though it could also be Buffy. Anyway, we get the sense that Beckett was a huge fan of Nebula-9 judging by how she blushes upon seeing its former star, Gabriel Winters (guest star Ed Quinn) in person. He captains the ship during the fan experience just like he used to do on the show.

"May fortune guide her journey." These are Gabriel's words for the deceased Annabelle, who was the driving force behind the resurgence of Nebula-9. It was also his catchphrase on the show. Gabriel steers Castle and Beckett towards Annabelle's friends, Audrey and Davis. They say the victim received death threats over the original webisodes she was making. Nebula-9 has a rabid fan base as Castle learns from an old college friend of Beckett's. The guy produces an old photo of her dressed as the show's sexy Lieutenant Chloe character. Beckett confiscates the photo under the guise of official police business.

Perlmutter determines that Annabelle died from a high-intensity laser beam through the chest. Castle believes "laser" means "phaser" before launching into his best Captain Kirk voice impression. A witness saw Annabelle walk into the ship with Stephanie Frye (guest star Christina Moore), who played Lieutenant Chloe on the original series. She has since gone on to make it big in the movies. She had no interest in getting involved in her old show's fan experience like Gabriel Winters, who happens to have a working laser blaster as part of his space outfit. Speaking of outfits, Castle freaks when he catches Alexis in a skimpy space costume at the convention.

Gabriel Winters alibis out for the murder, but claims Annabelle had a boyfriend. Ryan and Esposito check out a sci-fi party where Annabelle was seen with a Creaver, which is one of the nasty evil aliens from Nebula-9. As for the laser gun, Castle and Beckett track down its maker, Benjamin Donnelly (guest star Armin Shimerman), who has a really cool laser-filled lab. The guy is a purveyor of sci-fi hardware for the discriminating enthusiast. Castle shows interest in his double-bladed light saber, but Beckett would much rather see the plasma pistol that matches the murder weapon. He sold one to someone dressed in a Creaver costume.

The team tracks down Simon Westport (guest star Chris McKenna) who bought the live-fire laser weapon for Annabelle as a gift. They had a "same time next year" relationship whenever SuperNovaCon rolled around. Simon says she was upset after a having confrontation with her pal Davis, who semi-alibis out. Davis also mentions that Audrey gets all the rights to Nebula-9 now that Annabelle is dead. She just sold them for $2.5 million. Of course, Audrey denies killing her best friend.

Beckett asks Castle to stop making fun of Nebula-9. She loved dressing up as Lieutenant Chloe because the character didn't care what anyone thought of her. As for the show itself, it was silly for sure. But it was also about leaving home for the first time, searching for your identity and making a difference. Castle agrees to 86 all snarky comments regarding the show. This is just before he notices his hand glowing about the Nebula-9 ship. It's the same hand he used to fire the laser blaster. Beckett believes her partner just solved the case.

All prime suspects are brought aboard the Nebula-9 ship. Castle enlists Stephanie Frye's help to reenact the murder scene. He lets everyone know that the person who shot the blaster has a superficial burn on his or her hand that is visible under UV light. Gabriel Winters has just such a burn, but he's not the killer. No, the real murderer is his former co-star, Stephanie Frye. The original Lieutenant Chloe grabs the Nebula-9 captain's blaster. Gabriel Winters quickly overpowers her, as he knew his weapon was set on stun. He lets Castle deliver his catchphrase to the currently cuffed Lieutenant Chloe. Castle says, "And may fortune guide your journey."

Castle comforts Beckett now that the case is closed. It's always hard to see your idols fall. But Stephanie Frye wasn't really Beckett's idol. Lieutenant Chloe was. As far as Beckett is concerned, she's still out there fighting evil and saving humanity-just like a certain Earth-based couple we know. Beckett even gives Castle a treat by dressing up in her old Lieutenant Chloe costume. Too bad her super sexy space suit is topped off with a hideous Creaver mask. Hey, did you catch William Shatner belting out his "Ideal Woman" as background music? Kirk, out!