Jun, a neat and pretty student attending a girls' school in Tokyo, lives a happy life with her older boyfriend, Saji. Although Jun is from a single-parent family, he is wealthy, and Saji is actually dating Jun as a source of income. One day, Saji is in debt and is unable to pay off his debts. He offers Jun to a thug senior who he owes money to, in a plan to have the debt forgiven. From that point on, Jun becomes a constant user of Saji...