Da-kyung, who was an active member of a corporate criminal organization, belatedly learns of the death of her boss, whom she cared for like a father. Times later without knowing why her boss's death, she gets a clue, a college of rich people with most of the children of important people in Korea. Da-Kyung will go back to being a student to try to find out what happened, she is a well-trained assassin, but dealing with bullying and the stress of school life may not be as easy as it seems...