I heard about this some time ago but never got around to watching it. Supernatural horror film directed by Osgood Perkins, son of 'Psycho' star Anthony Perkins.

OP has three films under his belt now and they all have several things in common. Extremely slow pace, great cinematography, exceptional sound design, and polarizing effect on audiences. BD is an exemplar of all four.

Two girls - wallflower Katherine and streetwise Rose - are stranded at their all-girls school during winter break. We eventually find out Katherine isn't what she seems and has a dark mission to complete for her master. And there's a seemingly parallel B-story about a girl named Joan who escapes from a nut house and is trying to get to the girls school.

I'm a sucker for devil worship films so I give it the benefit of the doubt mostly. I don't mind slow burn horror, as long as there's a payoff. I liked the CONCEPTS behind the story more than the story itself. There's a mystery in the story that resolves itself by the third act but when you finally understand everything you may feel Perkins cheated, especially with the casting of Joan. But the ending is extremely effective.