Exclusive Video: Nathan Fillion Reveals Untold Firefly Secrets for Browncoats Unite

Do you think you know every Fireflyplot? Think again.

In this exclusive clip from Science Channel's Firefly 10th anniversary special Browncoats Unite, airing Sunday at 10/9c, the cast gathers to discuss behind-the-scenes secrets of the beloved gunslinging sci-fi series that ended after only 14 episodes. Star Nathan Fillion, who played Capt. Mal Reynolds of the Serenity ship, reveals an idea that series creator Joss Whedon had for an episode that never got a chance to be made.

Comic-Con: 9 shiny moments from Firefly's 10-year anniversary reunion

Check out the Serenity crew's shiny, untold adventure:

But before you watch Browncoats Unite, break out the chopsticks because you'll need plenty of grub for the daylong Firefly marathon that airs first, beginning Sunday morning at 7/6c. Afterward, the 60-minute special will uncover more secrets as part of an oral history of the franchise and will include exclusive cast interviews and this summer's raucous Comic-Con panel. Joining Whedon and Fillion for the fun are loyal crewmembers Sean Maher, Summer Glau, Adam Baldwin, Morena Baccarin, Alan Tudyk, Gina Torres and Jewel Staite, along with executive producer Tim Minear and executive story editor Jose Molina.

But wait, there's more! An hour just isn't enough to capture all the magic of Capt. Tightpants & Co., right? Turns out that some extra footage that didn't make it into special will be available for dedicated fans who take to Twitter. One of four videos will "unlock" for every 5,000 tweets that include @ScienceChannel and the hashtag #FireflyNov11 .

Got it? OK, let's Flock to Unlock or Capt. Mal will space you.

The Firefly marathon kicks off Sunday morning at 7/6c, followed by Browncoats Unite in the evening at 10/9c on Science Channel.