The Transgressor
聖獣学園 (original)
After the mysterious death of her mother, Maya takes religious vows to find out what terrible things happened to her mother inside the Sacred Heart Convent. As soon as the door closes to the nunnery, the nuns start torturing her. She also has to deal with a lecherous archbishops and a lesbian mother superior.
Starring Yumi Takigawa, Emiko Yamauchi, Yayoi Watanabe, Ryouko Ima, Hachiro Tako, Harumi Tajima, Natsuko Yashiro, Marie Antoinette, Emi Jo, Rie Saotome
It's a drama and thriller movie, and has a rating of 6.6 out of 10 from Imdb which is usually fine for this kind of movie.
Watch it here
Not found streaming from United Kingdom.