Chise and Akari are twins. They are so identical in appearance that people around them cannot tell them apart except for their parents and their childhood friend, Mayuki. The two sisters however, have their own personalities. Chise is shy and timid, making her unapproachable; Akari in contrast, is energetic and expressive, making her popular amongst boys in their school. But since they are so identical, boys often confess to Chise by mistaking her as Akari.

Akari doesn't show interest in the boys who intend to confess to her and Chise got used to it—being mistaken as her sister. There is just one thing that shakes their two small worlds though—Mayuki's attention. Deep inside a voice whispers to a heart "Why did there have to be two of us? God is so cruel..."