Tonight's episode of Castle can be summed up in one word: shiny!

Between the endless Firefly nods and super sci-fi cameos (hello, Principal Snyder!), "The Final Frontier" had us fangirling alongside our resident nerd in hot girl clothes, Detective Kate Beckett.

When a Nebula 9 megafan is found mysteriously murdered with a laser beam burn through her chest, KBecks and Rick Castle hit up a sci-fi fan convention to search for the killer. Their investigation leads to some shocking discoveries — among them, Kate's secret past as a Nebula 9 cosplay co-ed. Who knew that NYC's most sophisticated homicide detective was once a sci-fi-loving costume-wearing geek?!

Naturally, Castle finds her incessant fangirling completely adorkable — especially when she launches into a heartfelt soliloquy about how Lt. Chloe influenced her personal growth. And although the woman who played Lt. Chloe — deranged drama queen Stephanie Frye — turned out to be the killer, Beckett's love for Nebula 9 remains stronger than ever.

So strong, in fact, that Beckett pulls her Chloe costume out for one final go 'round of cosmic role play — which we're assuming is new territory for the sci-loving couple. In the words of Max Richards, "May fortune guide your journey!"

Did you love tonight's episode as much as we did? Rate "The Final Frontier" and tell us your thoughts below.

Lindsay Dreyer is an editor at Wetpaint Entertainment. Follow her on Twitter @LindsayNYC.


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