A story about a girl name Kwon Mira. She's have a crush on one of the famous guy in her school name Byun Baekhyun. This Byun Baekhyun guy is mean everything to her. Baekhyun made her smiles every day, she got butterflies in her tummy every time she saw him. Everyday after school, she will left a letter with KM as the sender in Baekhyun's locker. Baekhyun don't have the idea who is this 'KM' but he never tried to look for her. He thought that it will be a waste of time so he just let His locker full of Mira's letters. Even thought Baekhyun never know who she is, she's still happy with the fact that she got to see Baekhyun smiling everyday. But she's hiding something from everyone except for her family and best friend. She wants to tell Baekhyun on the letter that she don't have much time but she never got the courage, beside who is KWON MIRA TO BYUN BAEKHYUN ?