Heeseung, a gangster outside, a sucker for you. He has been always cool with his friends or anyone, except you. His heart always melts when it comes to you.

When it was his 6th birthday party, you kissed him as a gift, and ever since you did that, he named it as his best birthday party ever. You guys have been always classmates since elementary, 4th grade.

Now, it was his 21st birthday, you both are in college now. You were invited to his birthday party, as so as everyone.