When you were a kid, you're always gets bullied by your classmates when you were in kinder. One day, your classmate stood up for you and protect you. His name is Yoo Taeju, known for being the richest, smart and handsome yet cold and untouchable. He became your friend and you both were unseperable. One day, he promise to you: "When we grow up, i promise to marry you so i can protect and cherish you." He then gave you a promise necklace with heart shape... and so he did have the key necklace. And that day Taeju and his family move to another country. Even so, he stick to the promise he have made despite to the gap between you both

time skip

Its been 12 years passed and you are now in your first year and first day on college. As you were running at the hallway of the campus, thinking you'll be late, you suddenly bump into a tall guy. You stop a while to bow and apologize at him in rush. He look at you up and down, he then saw the 'heart shape necklace' you were wearing. He's not mistaken. You were about to run again when you felt a hand grab your wrist that makes you stop. He then spoke with his cold and deep voice.

"You're... Karl right?" He said as his free hand hold his key necklace