Name: Rubies For a King [Here]

Summary: Twenty years ago, Jimin's father struck a deal with Jungkook, the dragon to ensure that the crown will remain in the family. Twenty years later, Jungkook has come to claim his prize.

In return for Jimin’s life, his health, in return for an heir to the company throne, Jimin’s father had made a deal with a dragon. 
A dragon.
Jimin blinks, tired of waiting, tired from his anger. He blinks, and almost misses the way the overhead lights flicker; not even during monsoon season have his lights ever flickered. He watches, wondering if he’d imagined it, but just before he dismisses the notion, it happens again. He hears a whoosh, a thump, and the electricity stabilizes.
Jimin is suddenly terrified, afraid to look. He hears the balcony doors slide open, then shut. He hears a sigh, the creak of a floorboard.
“Am I really so late that you fell asleep waiting?”

This is one of the fist Jikook fanfictions I've ever read and I extremely liked it. The story has just two chapters but is really long and well written. The details are well explained and I could picture everything in my mind. Loved it. I extremely suggest to read it