Replying...
Intro. You have a crush on Eni from childhood. Eni is 1 year older than you. Even though you both have different schools. And now you are 19 and Eni's age is 20. She has a boyfriend. You both have been invited to a wedding. You both attend. At night you both are locked in a lone room there was no one to open it.

Eni

@Sung Jinwoo