MMM's University is of the prestige university in Seoul, South Korea. Only the elites and the smartest people got into it. Meaning that either you're richest or you're smarter than your peers then you will gets accepted.

In this case Moon Byul Yi got accepted because she's the elite. She's never interesting in academy side but she's definitely not dumb either. She is just not interested in education. However, she's a talented athletes. Especially running, bow, baseball and soccer. Not only that, she's also a talented dancer. She doesn't like to be a center of attention, being extremely good in sports means that you got no choice but to accepted and enjoying the fame.

Kim Yong Sun is a perfect child of the Kim's. She's smart, beautiful, friendly, cheerful and active. Not only that, she's also come from the elite family background. She is the head of the students council of MMM's University. Music is her life. She is extremely good at singing. In conclusion, she is good at balancing both academy and curriculum sides. 

Moon Byul Yi only got her father Moon Jae Hyun as her guardian. Moon Jae Hyun is a business tycoon. Owns a multiple of restaurants, hotels, resorts and casinos. Mr Moon been raised Byul as a single parent. He never talk about anything regarding his failed married. Byul never hear nor see her mother since born. She's desperately wants to know her biological mother but Mr Moon manage to blocked her every moves and tricks. Their relationship is not in a good condition. To avoided all those meaningless argument, Mr Moon will always outstation meanwhile Byul will be at any clubs to party. 

Kim Yong Sun the youngest Kim's always surrounded by love. She got a famous fashion designer sister, Kim Yong Hee. A pharmacist shareholder mother, Kim Hee Yeon. A shareholders of any kinds of multiples company such Apple, Google, Amazon and others famous brands all around the world. Kim Taek Sun. Although their family background remains mystery as they always stay grounded but they always gets attention from the crowd. 

Moon Jae Hyun always felt sorry for all the fight and miscommunication with Moon Byul Yi that he pampered her with wealth. He gave her a penthouse in Gangnam. A luxury personal car like Bugatti Veyron. A limousine to send and pick her up when she doesn't feel like to drive her own. Also a 100 million won as her monthly pocket money. 

Kim Taek Sun is a loving and supportive father for Kim Yong Sun. He did spoiled her but still strict at the same time. Kim Yong Sun got her own penthouse in Gangnam where she lived with her sister until she graduated. The rules is set by both of her parents that afraid their youngest child might be out of control if live by her own. Kim Yong Sun is just not always play by the rules type . She love her family but she just doesn't like to be too controls by them. Just a little bit stubborn and a mild rebel of the Kim's.