"You take the key necklace and I take the lock, we'll wear them all the time and treasure them forever. Someday when we're all grown up and meet again, you will use the key to unlock the lock I have and then, I promise that I will never leave you again and we can live happily ever after."
"I promise hyung that I will always wear the necklace all the time and treasure it forever until we meet again."
When they were young, Jimin and Jungkook were Best Friends, after school they always hang out with each other and they always stay with each other by their sides. Jimin and Jungkook secretly like each other that even their parents ship them together. Until one day, Jimin has to go to America for 5 years because of Jimin's parents. So Jimin gave Jungkook a key necklace while Jimin have a key lock necklace and promise each other that they will meet again.
Will Jimin and Jungkook meet again? Will they remember the promise that they have done when they were young?