Apostle

Apostle is a 2018 Gothic folk horror film written, directed and edited by Gareth Evans, and starring Dan Stevens, Lucy Boynton, Mark Lewis Jones, Bill Milner, Kristine Froseth, Paul Higgins and Michael Sheen. It had its world premiere at Fantastic Fest in September 2018, and began streaming on Netflix on October 12, 2018. The story follows a Welsh man as he attempts to rescue his sister from an unnamed cult on a remote island. The film received generally positive reviews from critics.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.

Poster © the film's rights holders.