Jungkook loved Jin. That was something that Jungkook acknowledged ever since their Skool Luv Affair promotion.

At predebut, Jungkook simply saw Jin as his a replacement mother. Having come all the way to Seoul without his family to support him, Jungkook looked up to Jin as not only his eldest hyung but a mother figure. Jin came to his graduations, drove him to school, cooked him lunch, pretty much not any different from an actual mother. Well... except for the gender and "giving birth" part maybe.

This admiration for Jin somehow turned into affection and love as Jungkook went through puberty. From a certain point when Jin ruffled his hair Jungkook couldn't help but blush a bit and his heart thumped anytime he saw Jin munching on food like a little rabbit. 

It wasn't until an accident occurred that Jungkook admitted to himself that he loved Jin.

He was filming a Bangtan Bomb with V, zooming into his face and stopping while V made various comments about his handsome face and the number of moles he had on his face. After a while of filming V, Jungkook spotted Jin sleeping peacefullly nearby. Being the mischievous maknae Jungkook went over to secretly film his hyung sleeping, zooming into his face while making the comments for him.

"I am.....Jin.......my shoulders.......are incredibly.........wide," Jungkook zoomed in closer and closer with each comment. Unconciously he closed in on his sleeping hyung's lips and ended up blurting out, "His lips are so thick..." 

He quickly ended the shot and went to film his own face, acting as if nothing happened but Jungkook finally admitted it. He was in love with Jin.

He didn't want to confess. He didn't want Jin to know. In Jin's eyes he was still nothing but a little kid and Jungkook knew that fully well.

When I turn 20..when I turn legal I'll confess. Jungkook decided at that point.

To Jungkook's delight, his body was maturing much faster than expected. His height had grown, biceps toned, abs formed, and he was already stronger than most of s, including Jin. And not only had his body matured, but so had his mind in general. 

He noticed this change in strength when Jin kept insisting that he wear a jacket over his red shirt because it was cold outside.

"Hyung I'll be fine I swear! It's not even that cold outside," Jungkook groaned as Jin continued to push the jacket towards his chest.

"Then you can take it off if it isn't! For now just wear it okay?" Jin held the jacket up. "Pretty please?" Jin tilted his head cutely.

Jungkook gulped and cleared his throat at his hyung's sudden aegyo.

"Ugh fine give it here!" Jungkook pulled on the jacket that Jin was holding. To Jungkook it was a simple pull but to Jin he felt like the pull could send him flying across the room. And it did.

As Jungkook pulled on the jacket he pulled Jin along with it, causing Jin to slam righ