هایونگ که یک دانش اموز است یک روز در حال پیاده روی قوطی یک نوشابه را شوت میکند و به طور اتفاقی می خوره تو سر یه راننده ی پولدار او با ماشین لکسوسش به دیوار بر خورد می کنه و ماشین حسابی خسارت می بینه هیونگ جون صاحب ماشین از دخترک طلب خسارت میکنه ولی دختر پا به فرار میذاره ولی هیونگ جون اونو از طریق کارت شناسایی دانش اموزیش پیدا می کنه از انجایی که دخترک وضع مالی خوبی ندارد هیونگ جون با او قراردادی با او امضا میکند تا او برایش به مدت 100 روز کار کند او خانه اش را تمیز می کند، کارهایش را انجام می دهد، ماشینش را تمیز می کند. اما بعد از مدتی دختر متوجه میشود که ماشین فقط 10 دلار خسارت برداشته بوده سپس شروع به انتقام از او میگیرد
After being dumped by her boyfriend just before their 100 day anniversary, Ha-Young (Ha Ji-Won), meets a college guy named Hyung-Joon (Kim Jae-Won) when she accidentally kicks a can that hits him in the face and causes him to scratch his Lexus. He demands she pay him $3000 on the spot. She escapes from him, leaving her wallet behind. Hyung-Joon stalks her, demanding money to pay for his car. Since she is a poor high school student Hyung-Joon writes up a "Enslavement Agreement" for Ha-Young in order to pay for the damage to his car. Ha-Young is thrown into a nightmarish slave life for 100 days, cleaning his house, running his errands, doing his homework and cleaning his car. By accident she finds out that the damage to Hyung-Joon's car only costs $10! She then takes her revenge. However, before she knows it Hyung-Joon shows up at her house as her new tutor! He once again takes advantage of her, but soon Ha-Young finds herself falling head over heels for Hyung-Joon. But what happens when he drops out of her life just when she needs him most?
