Chanyeol and Eunmi have been friends since birth. Living next door to each other, their parents being good friends, and even going to the same elementary school, they have known each other their whole lives. Until suddenly, Eunmi leaves without a trace just before the day that they were to attend the elementary school graduation, and leaves no way of contacting her or anyone related. Chanyeol waited for her, but it was in vain. Since then he has moved on, but he has never stopped thinking about her.