Minjeong decided to infiltrate the Party (an organization) with one reason and only one reason only-- to avenge her mother (Jessica) from the leader of that organization (Taeyeon) not knowing that she and that person are related. While staying in the organization, she got to know Karina and became close to her, even falling inlove with her. As time goes by, she got accustomed to her new environment, but she haven't forgot about her reason on infiltrating the org. Digging deeper and deeper, stumbling upon information to information, she unraveled the deepest  secrets of THE Kim Taeyeon and so as her mother. Upon finding out about these secrets, will she continue her plan? Will she choose something that will hurt her and Karina or will she let herself lose on her thoughts and conscience about family, love and friendship.