The serial murder case that was just resolved yesterday made Sehun relax a little today. He goes to the office just to check the profile he created for the of a teenage girl. 

"You came so early." Jiyoon came into the room and sat at her desk. Sehun turned his chair and pulled it closer to her, "You brought my order?"

Jiyoung throws a plastic bag filled with warm buns from the grocery store near her apartment. "Whoa, it's still warm. Thank you!” Sehun pulled his chair back to his desk and bites one of them.

"I still have another thing for you." Jiyoon smiled meaningfully. 

Sehun looked at her, seemed disinterested. "What?"

Jiyoon took something from her bag, a shabby pink letter with a little ribbon around it. She walked towards his desk and put down the letter on his table. "Letter from twelve years ago." She said with a pressing tone.

"What is this?"

"Letters for the future. You can't read?" She snickered.

"I know but what's that mean." He took the letter. "Is this for me?"

"The security guard at my old apartment called me that there was a letter in your name. That means the letter is from the past to the future today." Jiyoon back to her seat. "I wonder who sen