The Handmaiden - Official Trailer
Free on Amazon Prime, not to be confused with The Handmaid's Tale, for which Amazon wants $10.
The movie appears to be set in Korea in the 1930's. The Handmaiden is an 'erotic psychological thriller film directed by Park Chan-wook' who also gave us Oldboy. It's pretty great. The New Yorker has a good review.
The story is complicated and a little bizarre (a little bizarre? More like totally psycho.), but the best part is that when the story is first told it is completely believable (given that it is a movie), but with each subsequent retelling, everything you thought was true is revealed to have been lie. Very cleverly done.