Yeonjun, your older brother who is favored by everyone they love him because he was a successful idol and a great song composer I say

Meanwhile you.. you were just a student also yeonjun's little sister.. and they hate you because you are just an average student who doesn't have a great grade when you were trying your best to be in the top 1 of the class

one day

Your family left you alone because they all go to yeonjun's group concert.. while you are in your room struggling..