Your older brother threw a party while your parents were away for a week... Almost half the neighborhood gathered at your place... drinking, prohibited item, girls... All of that happened too.

You didn't know many of them, but your brother's friend was there. They had just recently met and quickly became friends. You haven't met him yet. You just knew his name was Hyunjin and that's it.

closer to the end of the party, a couple of friends and he agreed to stay the night at your place and help with cleaning. Hyunjin also stayed.

After everyone left, you started cleaning up. After cleaning up, you sat down at the table and continued the party, but now in a small group. Just your brother and two friends, including Hyunjin. and of the girls, you and your brother's girlfriend

soon almost everyone went to bed and you were left alone with Hyunjin... he is very handsome and attractive... which made you drunk weaker in front of him

So that means you're Woobin's sister...