Setoka Tachibana is a female high school student who has confessed her feelings to other boys 12 times, but has been rebuffed each time. Her older brother Haruka Tachibana cares for his younger sister deeply, but he keeps secret from her that they are not blood related. One day, Setoka’s first love Takane Serikawa appears after many years and approaches her.

Yu Akahane (Nana Komatsu) moves to a dormitory room after her father’s transfer from work. She is excited that she will live in the same dorm as Takumi Shirakawa (Yudai Chiba) aka “White Prince.” Yet, Haruto Kurosaki (Kento Nakajima) aka “Black Devil” kisses her as punishment for going against him. It is Yu Akahane’s first kiss. Since then, she becomes obedient to Haruto Kurosaki.