This is for those unfamiliar with the Firefly Universe or just looking for a quick refresher. If there's a need for additional details just ask or suggest they be posted.
By the 22nd century conditions on Earth became so bad that it could no longer support human life and humanity needed to find a new home. A new star system was discovered and plans were made by Earth’s two remaining superpowers (The United States & China) to colonize it.
The two terrestrial worlds that orbit the primary star make up the core planets. One is predominantly Western in culture, the other pan-Asian. This fusion of Western and East Asian cultures results in mixed linguistic and visual themes for our game. The dialogue tends to be a bizarre purée of wisecracks, old-timey Western-paperback patois and snatches of Chinese. (Which is why we curse in Mandarin, but feel free to use English or refrain all together.)
The core planets are the base of power behind the governing and military body called The Union of Allied Planets or simply The Alliance. Their power and control extends to the other planets, but the further out you go the less it means. The central planets are firmly under Alliance control, but the outlying planets and moons resemble the 19th-century American West, under little governmental authority. Settlers and refugees on the outlying worlds have relative freedom from the central government, but lack the amenities of the high-tech civilization that exists on the inner worlds. In addition, the outlying areas of space ("The Black") are inhabited by the Reavers, a cannibalistic group of nomadic humans that have become savage and animalistic.
There was resentment between the outlying worlds and the Alliance. It resulted in the Unification War, a failed attempt by the outlying worlds (the Independents) to resist the Alliance's control. The resistance fighters of the outer planets were known colloquially as Browncoats due to their customary brown trench coat and attire. They lost completely, lacking the resources to wage a proper war in the first place even if they possessed the heart. Years later that division between the rich and poor still exists. The resources and financial aid promised by the Alliance in the wake of the war was short lived and did little to improve the lives of those living outside the practical control of the Alliance. A veteran Browncoat soldier went on to scrape a living doing the odd jobs with his ship, some of it was even respectable work. But the winds of discontent are blowing again and people are talking about a Second Unification War. Once you put on the Browncoat you never take it off and if there was going to be another war, Captain Keller would be there to fight the good fight. But wars required resources and they’d lost the first one precisely because they lacked those resources. He needed allies and money which meant he’d be doing some good deeds for good people and some bad deeds for worse people. But first he’d need a crew.