Space cowboys, space hookers and no ugly people. That's the future of the human race.
Firefly lasted for 14 episodes before Fox cancelled it citing low viewing figures, distinct lack of potential for a reality show spin-off and not enough gun-toting space hookers. They aired 12 episodes, cutting the show loose before the airing of 'Heart of Gold', which ironically was 40 odd minutes of space hookers shooting at things. The two unaired episodes wound up on the DVD, which went on to sell more copies than The Bible and the Koran combined as every Firefly fan bought at least six copies to aggressively loan to their unenlightened friends. The success of the DVD vindicated the decision of Universal pictures to greenlight a movie which would tie up all the loose ends of the series. Of course the Firefly fans who had boosted the DVD sales then assumed it was them who had gotten the movie made and became largely insufferable, strutting round Comic-Con in their Captain Mal get up nodding "You're welcome" to Universal Execs and proffering their wisdom to every poor schmo whose show had just been cancelled.
Picking up roughly six months after the events of the series, the movie Serenity tied up many of the loose ends that Firefly had left dangling. We find out happened to River Tam when she was abducted by the government, and meet The Operative, assigned to capture her so that the wacky secrets in her head don't come spilling out and bring down the Alliance. We also see the making of the Reavers - a troupe of cannibals who look like escaped mental patients at a Predator lookalike contest. There's some other stuff about the nature of freedom, more eye-fucking that is strictly necessary and a hell of a lot of fight scenes, this being a Whedon product. Also, as you might imagine, Joss Whedon uses the last twenty minutes to turn every fan of the series into a weeping, foetal ball and you start to wonder whether any of the characters are going to live through the movie.
Serenity didn't perform badly at the box office, again the ticket sales were bolstered by fans seeing the movie five billion times each and making papier mache effigies of Fox Executives out of their ticket stubs which they then burned and danced around. Probably. Rumours of another movie were quickly squashed and the Firefly fans went about their lives, never dwelling on what could have been. Oh no, wait...
Having tasted victory once, the Browncoats (Firefly fans ironically named after the resistance soldiers who never could quite let anything go) persisted in keeping their show alive. Because the series had been of little commercial interest to Fox after the cancellation, a kind of unofficial amnesty had been called over the likes of image rights and trademarks. Thus a booming trade started in Firefly related t-shirts and other merchandise, until Universal stepped in and tried to claw back some of the money from what was now their property. The fans revolted and sent Universal scurrying with a website called Browncoatinvoice.com (now redirects to an unofficial site for Mutant Enemy Productions, Whedon's company) which detailed the cash value of all the free advertising and promotional work the fans had done for the movie. Charity screenings of Serenity continue to this day to raise money for Joss Whedon's favourite charity Equality Now and there remains a stronghold of Firefly fans who are still merchandising, promoting and flogging that horse corpse.
Remember when your boyfriend dumped you and you spent countless hours hugging that old sweatshirt he left at your place, sobbing and re-reading his text messages for any secret code which might say "It was all a prank! Meet me at midnight on the common and bring your box of tissues that I used." Remember that? No? Okay fine, whatever. (David, if you're reading this, it means you still love me.) Anyway, the fans of Firefly raped the text for anything they could cling to as a reminder of better times. People knitted 'Jayne hats', a woolly hat worn by one character once in one episode for about three scenes, and juggled stuffed geese in reference to a throwaway line in the episode 'Our Mrs Reynolds'.
In the series the two surviving super powers are the USA and China, so aside from the show's own dialect terms ('Shiny' meaning 'good' and 'verse' meaning the universe) the script was peppered with Chinese sayings. Any assembly of Browncoats (or 'shindig') will look like a cross between the OK Corral and downtown Shanghai.