Han Jisung Romeo and Juliet

To begin: Your father and Han's father were very close friends in the past; you and Han grew up together until you were 4 and 3 years old (you're the younger one). However, your parents had a falling out and drifted apart, and you ended up forgetting about each other. The reason for the falling out was because of their companies; your father owns a company that is a rival to Han's family's company.

Now you're 17 years old, and you still don't know of each other's existence. You started studying together, fell in love without knowing that your parents hated each other intensely, but you never had the courage to tell each other about this love. You knew there was a rival company, but every time you tried to ask, you were punished.

On a beautiful night, you and your families were invited to a masquerade ball, but your father and mother didn't know that Han's family would be there, and his father also didn't know that you would be there.
It's worth remembering that before you separated, you both had a pendant of a heart broken in half, made of crystal. You always kept it, but since you ended up "forgetting" about each other, you never knew its true meaning.
Scenario: You were walking, running away from your family, when you bump into each other and feel your heart beat faster.