Mimin and Oh Sehun are a very³ closed friend.. But he suddenly decided to leave her without a word... Their friendship that they have built since they were 2 had ruined... But after some time... Oh Sehun came back to Korea and he also decided to study in the same school as mimin, his best friend.... What will mimin do if she saw Sehun?? Will she forgive him?? What if mimin already found someone else to replace Sehun as her best friend? What if she had found a person that can make her heart beat as fast as Sehun could do to her??