The crew of Serenity take on a train heist commissioned by a crime lord. They steal the goods, only to find it is medicine that's desperately needed by the town.

Serenity encounters a ruthlessly professional bounty hunter, Jubal Early, who will stop at nothing to retrieve River. But River, feeling unwelcome on the ship, takes a novel approach to escaping from the long arm of the Alliance.

Malcolm Reynolds is a veteran and the captain of Serenity. He and his crew are smuggling goods, but they need to pick up some passengers for extra money. However, not all the passengers are what they seem.