When the renegade crew of Serenity agrees to hide a fugitive on their ship, they find themselves in an action-packed battle between the relentless military might of a totalitarian regime who will destroy anything – or anyone – to get the girl back and the bloodthirsty creatures who roam the uncharted areas of space. But... the greatest danger of all may be on their ship.

故事发生在遥远的未来世界，此时，人类对于太空的勘探已经发展到了成熟的阶段，梅尔（内森·菲利安 Nathan Fillion 饰）是太空船“宁静号”的船长，每一日，梅尔都驾驶着他的“家”，穿梭在浩瀚的宇宙之中。 宁静号拥有九名乘客，这九人地位悬殊，个性迥异，每一个人都有着一段不可告人的灰暗往事，而他们脱离陆地登上宁静号，亦有着各自不同的理由。九人唯一的共同点在于，他们都是地上世界中的“刺头”。为了维持生计，宁静号接纳一切能够赚钱的任务，其中甚至有些看起来并不是那么合法，与此同时，梅尔船长亦要带领他的船员们设法逃脱联邦政府的追踪。

In 2071, roughly fifty years after an accident with a hyperspace gateway made the Earth almost uninhabitable, humanity has colonized most of the rocky planets and moons of the Solar System. Amid a rising crime rate, the Inter Solar System Police (ISSP) set up a legalized contract system, in which registered bounty hunters, also referred to as "Cowboys", chase criminals and bring them in alive in return for a reward.