Мой брат слишком сильно меня любит

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.