Loved this movie, just watched it and it was mesmerizing ...so well done! Now ava on Amazon Prime. I just figured out this was based on a book by Sarah Waters called Fingersmith, which I read... I also saw the mini series based on it...

https://www.themoviedb.org/tv/13812-fingersmith

Now I know why the plot seemed so familiar. I should of figured it out when watching it... I just don't have a good memory these days.