"Serenity" is the two-part series finale and the original intended pilot for the American science fiction television series Firefly created by Joss Whedon. It was the first episode produced for the series and premiered on Friday, December 20, 2002 on Fox. With studio executives unsatisfied with the episode for the series premiere, the show's second episode, "The Train Job", was re-written and produced as a second pilot to be aired first. The episode shares its name with the 2005 feature film Serenity, which serves as a continuation to Firefly.