Interesting little folk horror film, based in the UK (I believe).
For me, it was slow, as in too slow. It also answers questions to easily, as in the main character sets out to find out what happened to his sister, and like a video game, he goes to A, then A sends him to B, and so on, until the mystery is revealed.
Surprising ending that works for the most part, makes you stop to think about things, which is always a good thing.
It's very well filmed and shot, and the English countryside is gorgeous.
Give it a shot and see what you think.
Grade - B-