As the leader of a debt collecting company, An Yamo threatens people and acts cute. When she acts pitiful, nobody can resist her. Once she takes action, there is no debt she cannot collect. But one day, she meets a tough opponent. Since phone calls don't work, she brings her men to knock on his door, only to discover that he is a super handsome boy who is actually her schoolmate! Handsome boy: "If you don't want to be exposed, become my slave~" Thus, the school life of the tyrannical girl and the sadistic prince, which is full of battles and clashes, begins.