Yeon-Woo, the heir of the organization Sipgangpa, disguises herself as a boy to infiltrate an all-boys school and eliminate the heir of the rival organization Makgangpa. However, as she catches the attention of a handsome trio, romance begins to blossom in her used-to-be noir life. One of the three is apparaently the heir of Makgangpa—will Yeon-Woo be able to complete her mission without falling in love?