Five hundred years in the future, Captain Mal Reynolds, a hardened war veteran (on the losing side), ekes out a living pulling off small crimes and transport-for-hire aboard his ship, Serenity. He leads a small, eclectic crew who are the closest thing he has left to family — squabbling, insubordinate, and undyingly loyal.
When Mal takes on two new passengers — a young doctor named Simon and his unstable, telepathic sister, River — he gets much more than he bargained for. The pair are fugitives from a coalition that dominates the universe with unlimited wealth and power — and that will stop at nothing to control River and her abilities. The crew of mercenaries, used to skimming the outskirts of the galaxy unnoticed, soon find themselves caught between the unstoppable military force of the Universal Alliance and the cannibalistic fury of the Reavers, savages who roam the very edge of space. Caught up in the fight to stay alive, they don't yet realize that their greatest danger may be on board Serenity herself....