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...