Her (1970)

On their wedding night, groom Apo catches the bride with her stepfather, Chawin, who attacks Apo to protect their secret. Apo is mutilated and believed to be dead. In order to seek vegeance, Apo becomes a woman and installs herself as Chawin's secretary. In this position, Apo gets to know a member of the family, Porpan, and identifies her as their weakness...or her own.