The Final Frontier
Season 5, Episode 6
Air date November 5, 2012
Written by Kate Sargeant
Directed by Jonathan Frakes
Episode guide
"Probable Cause"
"Swan Song"
Castle Season 5 cast
Season 5
Season 5 is now available on DVD.  

1   •   2   •   3   •   4   •   5   •   6

7   •   8   •   9   •   10   •   11   •   12

13   •   14   •   15   •   16   •   17   •   18

19   •   20   •   21   •   22   •   23   •   24

Season 4   Season 6

The Final Frontier is the sixth episode of the fifth season of Castle.


When a body is found at a sci-fi convention, Castle and Beckett are warped into the heart of fandom—a world of egotistic celebrities, diehard costumed fans and enough drama for two galaxies.



Castle 5x06 The Final Frontier US Promo (HD)00:31

Castle 5x06 The Final Frontier US Promo (HD)


Main Cast

Guest Cast


Beckett: I thought you would be a fan.
Castle: I'm a fan of good sci-fi. Star Trek. Battlestar. That Joss Whedon show. But "Nebula 9"? No, no. It's all phony melodrama and lifeless acting.
Beckett: So, I was a Nebula-9 fan. Big deal.
Castle: Oh, you were beyond a fan. You dressed up in costume. You.
Beckett: Okay, yes. I was a sci-fi loving, costume wearing geek. And you know what? Not ashamed of it or of Nebula-9. Despite what you think, it was an awesome show.
Castle: Hmm. I’ll tell you what. I’ll forgive you your terrible taste if you ... try on that Nebula-9 costume for me.
Beckett: In your dreams.
Castle: Look at my life. My dreams come true.
Castle: Annabelle said she was betrayed by someone she trusted. Maybe that was Captain Max. Oh, my God! Alexis?
Alexis: Dad? What are you doing here?
Castle: What are you doing here dressed like that?
Alexis: We're Havacura. It's a tribe of female assassins who –
Castle: Don't wear clothes?
Alexis: You're overacting. And you're embarrassing me.
Castle: Oh, I'm embarrassing you? I'm the one who's dressed.
Alexis: Dad!
Beckett: Castle, come on. Let's go.
Castle: Are you kidding me? Do you see what's she's wearing?
Beckett: Yeah, it's not that bad.
Castle: Not that bad? How am I gonna unsee that?
Castle: Some guys have no business commanding a spaceship.
Beckett: Just goes to show you sometimes people aren’t what they appear to be.
Castle: For Alexis’ sake, you’re right, given what she was wearing.
Beckett: Castle, she is a full-grown woman.
Castle: Who, as we speak, is being ogled by thousands of sweaty, lecherous fan boys. It’s just so...wrong.
Beckett: Can I just point out the fact that the costume she was wearing is not so different from the one you are asking me to wear?
Castle: Don’t say that!'s confusing and disturbing.
Castle: Sexy dreams? You know, it’s never too late to live out your fantasy.
Beckett: You do realize that this is still a crime scene?
Castle: Oh, right. Ew.

Featured Music


See Sci Fi References in The Final Frontier for a full listing of science fiction references.

  • Director Jonathan Frakes has a small cameo as Castle's number one fan. After Castle signs his copy of "Storm Season" Frakes exclaims "Thanks, I'm your number one fan!" to which Castle replies " far they fall."
  • Chris McKenna played Joey Buchanan in One Life to Live, the same character that Nathan Fillion played when he was on that show. McKenna played the role from 1990 to 1993 before Nathan took over the role in 1993.
  • In "Tick, Tick, Tick...", Castle suggested that Beckett (and suggested Nikki Heat alter ego Kate Beckinsale) could go by the nickname "K-Becks". In "Food to Die For", her high school friend Madison called her "Becks". In this episode, a friend reveals that her nickname at Stanford was indeed K-Becks.
  • Esposito recognized the Kreever alien and reviewed its habits for Ryan, suggesting that he, too, is a closeted Nebula 9 fan.
  • Winters was held at gunpoint while the killer admitted to her crime, then struck and disabled her... only to reveal that the gun was on stun all along. This is essentially a reprise of Castle apprehending the killer in "Flowers for Your Grave".
  • Stana Katic voiced "the Oracle", the ship's computer on Nebula-9.[1]
  • Someone in a Lone Vengeance costume is seen when Castle is talking to Alexis. Later in the episode, an another Lone Vengeance costume can be seen when Detectives Ryan and Esposito are at the convention center bar.
  • The show Castle has A LOT of things in common with the 80's show Remington Steele staring Stephanie Zimbalist and Pierce Brosnan. In that show the main character Laura Holt (played by Zimablist) is a strong self-confident woman working in a male oriented environment (a detective agency) and Pierce Brosnan plays the handsome, charming vagabond who cons his way in to her life and helps her solve cases with street smarts and an array of movie-references. The two flirt and shares the occasional kiss but doesn't get in to a proper relationship until season 5. Pierce Brosnan's character also searches for the real identity of the father he has never known. Even the show intro from seasons 1-3 in Castle where Richard Castle in a voiceover explain the shows premise is reminiscent of that of Laura Holt's voiceover in the intro of the first seasons of Remington Steele - more to the point - they also have a case in a comicon and Laura also turns out to be a "fangirl" of a fictional hero, to the point of getting in costume imitating her hero, very much like Beckett in this episode.
  • When Castle is told that the murder has to do Nebula-9, he dismisses it as not a quality sci-fi series, then names off a few, including saying 'That Joss Whedon Show', referring to Firefly.
  • This marks the third time Richard Castle made a reference to Firefly; the second time being from the episode Close Encounters of the Murderous Kind, when he mentions his speaking of fluent Chinese. The first time was in the episode Vampire Weekend when he dressed in his Captain Malcolm Reynolds outfit.
  • Castle sounds excited at the prospect that the murder could've been committed by a Cylon skinjob, particularly if it was Number Six. Nathan Fillion has dated Tricia Helfer, the actress who played Six in the reimagined Battlestar Galactica.
  • Early on in the investigation, as Beckett and Castle are walking through the convention, a priest who resembles Caleb, the character Nathan Fillion played on Buffy, walks by them.

TV Show References


  1. CASTLE: Director Jonathan Frakes on his ‘The Final Frontier’ Cameo... Retrieved November 20, 2012.

Start a Discussion Discussions about The Final Frontier

Ad blocker interference detected!

Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.