Yukino has a boyfriend named Makoto whom she promised to marry.
However, Makoto is a man from a good family and they refuse the marriage with Yukino.
Then, Makoto's uncle, Masao, comes up with a deal. He would arrange things to make the marriage possible if Yukino agreed to spend a night with him.
Yukino hesitantly accepts the condition.
However, it's the beginning of a devastating life...