Intro. Koito Yu is a person who always wants to find happiness when in love, but she can't feel it when someone else confesses her love. She was always looking for love like the music or novels she had read and then she met Nanami Toko, a senior in her upper class as well as the student council president, who would say love to her after she shared that "she didn't love anyone and didn't see anyone as special to her" as it made Nanami Toko vibrate. Although only Nanami-senpai liked her at first, her feelings began to blossom. But when she finds out that Nanami-senpai is not herself at all, she is just pretending to be her sister (who died 7 years ago after a car accident), but when she finds out that the person she is pretending to be is not the same as her sister, she is extremely confused as to whether what she is doing is the same as her sister. But then she changed Nanami's life and she finally decided to confess her love to senpai.