The film originates from a genre called 'internet fiction. This popular internet fiction was later released in the form of a four part book series that was later turned into a movie. Although there are many scenes that were taken out and also added in place, it was a big hit around that time to create movies that derived from 'internet fiction' stories and writers.
After being dumped by her boyfriend just before their 100 day anniversary, Ha-Young (Ha Ji-Won) meets a college guy named Hyung-Joon when she kicks a can that accidentally 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, running his errands, i.e.: cleaning his house, carrying his shopping, and cleaning his car.
By accident she finds out that the damage to Hyung-Joon's car that's only $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?
The original Korean title can be literally translated as "my love, the asshole," or, more roughly, as "my love, the no-manners".