7am, Seoul High School, before class.
Venue: Shoe locker no. 37

A pink envelope beckons Lu Han to open it up as he stared at it on his hands.
A big red heart drawn on the cover.

In his 19 years alive, he was the boring, quiet, nerd in class.
He may not wear big round spectacles or carry stacks of books around in school, but his bob hair cut, made the whole school somehow stereotyped him.
Adding on, his grades were consistently the top few of the cohort.

Who wouldn't make fun of such a nerd like that?

So while everyone jokes of how his hair is related to his grades, Lu Han just could not come up with any legit female names in school who could possibly be interested in him.
Heck, Lu Han knows his face best, because...

He is, unlike a certain 'Kingka' (whatever ka his schoolmates like to call) - Oh Se Hun, standing on the other side of Lu Han's locker.

Se Hun is the popular guy in school, Lu Han is the mushroom hair with good grades.
Se Hun is helpful, socially desirable, ace in basketball. Lu Han is also helpful, not very socially desirable, ace his grades.
Divided by just a locker between them, it seemed to cut the two guys in two different worlds.

Although Se Hun gets decent amount of love letters in his shoe locker every now and then, he reads and politely rejects each and every one of them.

Did none of them actually matched his taste at all?

But that day, while Lu Han receives his first love letter, Se Hun, for the very first time, accepted a girl's feelings from the history of piles, of love letters.