Hong Seol and Yoo Jung attend the same college, but they couldn't be more different. Hong Seol is a poor, unpopular student with no money, while Yoo Jung is rich, well-liked, extremely smart, and popular.
A new born girl is placed in a coin operated locker in the subway station. The girl is raised by a mother (Kim Hye-Soo) who is the boss for a loan shark group. Later, when the girl has grown into a teen, she carries out missions given to her by her mother.