The movie Serenity was resurrected from an earlier Joss Whedon television show Firefly. It answered the big question about why the government so badly wants to find River, a young girl. The crew of Serenity finds that a secret government program with the intent to make people better (more compliant, more controllable) resulted in the death of a entire planet of people, Capt. Malcom Reynolds decides to expose them.
Capt. Malcolm Reynolds: This record here’s about twelve years old. Parliament buried it and it stayed buried until River here dug it up. This is what they were afraid she knew. And they were right to fear. There’s a universe of folk who’re gonna know it, too. Someone *has to* speak for these people.
Y’all got on this boat for different reasons, but y’all come to the same place. So now I’m asking more of you than I have before. Maybe all. Sure as I know anything, I know this – they will try again. Maybe on another world, maybe on this very ground swept clean. A year from now, ten? They’ll swing back to the belief that they can make people… better. And I do not hold to that. So no more runnin’. I aim to misbehave.
From IMDB: The crew of the ship Serenity tries to evade an assassin sent to recapture one of their number who is telepathic.