The best way I can think to summarize the plot is: Romeo and Juliet</a> crossed with Hamlet... except with Mormons.
And by that I mean that there is a fictional love story, overlaid with a massacre. The Mormons are on the one side, and the "Mericats" are on the other... they would be Americans, and in particular, anyone associated with Missouri. There is a lot of religious hatred flying around. And predictably, the traditional Christians are portrayed as meek and godly, and the Mormons as devils.
The film is both disturbing and deeply mediocre. It's based on a true story. Indeed, it is a decent historical example of religious fanaticism run amok, but I doubt that the people that it is aimed at will heed the message being sent to them.
And to think I have a cousin that converted into that religion. I keep telling myself it's no worse than Catholicism...