Setoka Tachibana (Tao Tsuchiya) is a female high school student. She has confessed her feelings to other boys 12 times, but has been rebuffed each time. Her older brother Haruka Tachibana (Ryota Katayose) cares for his younger sister deeply, but he holds a secret from Setoka. The secret is that they are not blood related. One day, Setoka's first love Takane Serikawa (Yudai Chiba) appears after many years and approaches her.