Release date 2005:

Once thought only to be fictional, Miranda in fact was an experimental colony where the Alliance tried to chemically modify its populace to be peaceful. This worked too well; it eliminated violence, but in the process it had a fatal side effect. The inhabitants lost all ambition; they stopped doing any work, stopped talking to each other, stopped reproducing and eventually stopped even feeding. For 0.1% of the population it had the opposite effect and caused extremely violent behavior, beyond mere psychosis but animalism. The "survivors" of Miranda were the Reavers who started to menace the Rim planets.

The Alliance managed to cover up their mess fairly well, erasing all official records of the planet. Those who had heard talk of Miranda heard false tales that terraforming was attempted but ultimately failed, and that the planet was an uninhabitable Blackrock. Of course, being in the heart of what was to become Reaver space, not many people made the trip to see if it was true or not.

River Tam had knowledge of Miranda through gleaning it from the mind of one of Alliance Parliament officials who surveyed her during her training, which was one of the reasons the Alliance sent the Operative to retrieve her. When the Alliance recording was discovered, it became the perfect example of what would happen if the Alliance sought to interfere with self-determination. At risk of their lives from both the Reavers and the Operative, the crew of Serenity used Mr. Universe's broadwave equipment to transmit a recording of what the Alliance did on Miranda to every planet and moon in the system.