During a rainy day, Samon stopped at a flower shop to take shelter from the storm. There he met Koito, the girl from that store that goes a year behind him at school.

After that, when he finds himself involved in the love affairs of his classmates and finds himself alone in his class, Samon projects his fury on Koito saying "What amuses you so much so that you are always smiling?", And ends up hating himself. That made Samon anxious, and on graduation day, for some reason, Koito gives him a diary.

Actually, Koito admired Samon. In that newspaper he said "Life during middle school was fun because you were there ...". Despite hating himself, Samon likes the things written about him in Koito's diary. Time passes and, upon entering the second year of high school, he reunites with Koito, who entered that school following him...