I forgot to mention that since this story is going to be taken like a diary (as you already see), the chapters are going to vary a lot in length (meaning not all of them will be at least 1,000 words).

Junhui looked at the house yet again after stepping out of his house, wondering if whoever lives in there would ever take a good look outside, but it seemed like they had a phobia of people. He thinks that maybe, one day, they would be able to see each other for the first time if this letter exchange continues to go well.

Finding a more convenient way to exchange should be my first step though... he lets out a sigh at the realization that climbing up and down a tree without the owner's (especially if the person he's talking too isn't even the owner of the house) permission is extremely inconvenient but he'll have to deal with it for now. A quick glance at his surroundings for anyone before he makes a move to climb up the tree.

Once he reaches the spot, he notices that a little piece of tape is stuck to the outside part of the window and couldn't help but smile at the sight of it. He sticks his letter to the tape but had to pause from climbing down the tree when he hears the door to the front of the house open. Through the leaves, he's barely able to make out the figure of a girl that looked around Hansol's or Chan's age locking the door before walking off.

A little sister maybe? Junhui ponders a bit before nearly freaking out when hearing a crack beneath him. He quickly makes his way to get off of the tree before he could fall down and hit the ground.

When he got to school, he didn't quite expect his friends to immediately tease once he gets to school- which got on his nerves greatly. Junhui sighs loudly before saying loudly to stop their chattering, "Fine, do you really want the truth?"

He took note as to how his friends nod excitedly and perked up like meerkats, which really said how interested his friends were in his love life. Although it was kind of interesting, it was also kind of bothersome but he dealt with it somehow, "I've been leaving letters for my neighbor but before you go assuming things, I'm going to say very clearly that I don't even know who they are and that they seem to have a phobia of people, okay?"

This immediately makes them quiet, put a little bit of thought into it, before going off with their normal chats, which Junhui was eternally greatful for. The only one who didn't continue on was Jisoo, who lagged a bit behind their walking group to continue to talk to Junhui.

"So you guys have just been talking to each other like penpals?" Jisoo asked curiously.

"I guess you can say it like that... although I kinda called myself a squirrel instead of putting my actual name," Junhui murmurs, making Jisoo chuckle.

"Any idea if mystery person is someone you know?"

"Not really, doesn't seem like it considering that one of their letters talked about wondering what the world is like, so it's easy to tell that they haven't been outside in a long time... then again, all of his letters are vague to say the least..."

"How so?"

"I dunno, kinda like they were meant for someone?" Junhui wasn't so sure himself, but there was a lot of hesitance shown in how the person wrote where it seemed as though they were letters meant for someone instead of something similar to a diary entry. If only he could figure out for who.

That evening, when he reached the street, he saw that a pastel orange plane had flown down to the white street before the sound of a window closing echoed throughout the empty streets. He hurries back to his house and to his room to read it.

It's okay (it's cute). My name is 1004... or at least that was the nickname my old friends gave me.
~ Dec. 28, 20XX                                                                                                                                                          
P.S. You spelled letter wrong.                                                                                                                                 

He felt happy, knowing that the person was at the very least beginning to trust him and not seem as terrified about him. A smile eased onto his face as he grabs a piece of paper and blue pen to write down a proper response to give to the person.

Well in that case, my nickname is Jun (not Squirrel-nim, just to make sure).
~ Dec. 28, 20XX        
P.S. I was embarrassed, okay?

It was nice to finally have written a letter where he didn't feel awkward about the idea of giving it the next day.

"Hyung, what are you doing?" Fengjun kind of scared him when he suddenly saw his little brother right by his elbow. After his heart calmed down, Junhui ruffled Fengjun's hair, replying, "Writing a letter for someone," and folds the paper before placing a sticker of another bear on it.

"For who?" Fengjun looks up curiously.

"For... a friend," Junhui would have chosen acquaintance but figured that Fengjun wouldn't have known the extremely formal word yet, especially since he was still learning Korean and trying to learn Mandarin at home.

"Is your friend nice?"

To that, Junhui had to put a bit more thought into before deciding on, "Well, they wouldn't hurt a fly," since he wasn't quite sure as to what the person was like other than lonely and insecure from all of the letters he had read (which he kept in one of the drawers of his desk), "Go to bed before mom scolds you."

Fengjun listens to Junhui as usual, leaving the latter to stare at the pastel orange paper, thinking that it was odd that someone who seemed rather gloomy would use such colorful papers to write on.