A Secret That Can’t Be Told (2016)

19금 정사: 말할 수 없는 비밀 (19-geum jeong-sa: mal-hal su eobs-neun bi-mil)
Directed by Park Bum-soo (박범수)
Cast Sunny-I (써니), Yoon Ah (윤아), Stew (찌게)
•Erotic •Melodrama •Romance
70min | Release date in South Korea : 2016/08/18
Synopsis
Two women start living with a man who lives alone.
The women introduce themselves as sisters looking for their long lost father and they start to seduce the man. Actually, these women are a serial killing duo who only target men who live alone. In the end, the man loses his life. While they are celebrating, a boy calling himself the man’s brother, appears in front of them one day. He looks and sounds just like the man but has a completely different personality and he’s nothing like the two women has ever seen before.