Shim Changmin and Park Soojung have always been friends since she moved next door to his house when she was four. Being the bestest of friends, they did everything together! They had sleepovers, went to school together and played at each other's houses all the time. Soojung liked calling him 'Oppa Cousin' but he just prefered 'Changmin-oppa' or just 'Oppa'. They were like family, he was her protective big brother. They were the happiest kids in the world until the start of high school (Junior High), when he became different. He grew up, taller and more handsome too. He made new friends and they slowly drifted apart.

Soojung still doesn't know why they were like this but she moved on and made new friends. However, deep inside she still missed her oppa.