From the Introduction:
This setting and rules conversion assumes ownership and familiarity with both the Savage Worlds rules (2nd printing preferred) and the Serenity Role-Playing Game. All setting material in the latter game is considered canonical. If you want to play a game where the movie never happened, very few adjustments will be necessary.
Some of the rules printed below were adapted from or inspired by various sources, including J.L. Herbert's version of Firefly for Savage Worlds and several Great White Game/Pinnacle products, including the Adventure Deck rules, Necessary Evil, 50 Fathoms, the 50 Fathoms Companion, and Deadlands Reloaded. Other sources are Jamie Chambers' Serenity RPG published by Margaret Weis Productions, Ltd. and GURPS Traveller, written by Loren Wiseman and published by Steve Jackson Games. This work is not intended to be a challenge to anyone's trademarks; if you're unfamiliar with any of these games, you should go buy them. They're really good.