Chapter 1: The Fire

Minseok and Xiumin are twins with very different personalities. They lost their parents at a young age hence they got adopted into an orphanage. They met a girl from the same orphanage, Eunseo. She lost her parents in a huge fire just a few years ago. However, she is a very cheerful girl who never fails to make someone's day. The trio soon became good friends. Several years passed and just when everything is getting better, a couple decided to only adopt Xiumin. Minseok and Eunseo got adopted a few weeks later. All of them got adopted by different families, losing contact with one another.

Years later, Eunseo happens to meet a similar figure.