Good movie. Not perfect but if you can wrap your head around the psychology of both the heroine and the antagonists the ending makes perfect sense (although there is a fine, almost invisible thread that allows for a sequel). Sure, it starts off with the conventional spooky stuff (and that was well done), but the deepening emotional reservoir and determined resolve of the main character is what really drives the third act. The main question - why was the main character allowed to complete her journey - lies in the way her value is determined by the antagonists... in some ways, she's more like them than her own people; hence, she escapes the usual fate. But of course, in that mercy lies the backdoor to a sequel...