Jung Nayeon, 18 years old, the daughter of Jung Taewon, the current CEO of Hyundai, the number one car company in Seoul, South Korea. She lives in Seoul with her rich, drunk and abusive father alone. Her mother had taken her older sister, Nayoung and ran off, leaving her youngest daughter behind. Luckily, she has her boyfriend, Kim Mingyu by her side. 

Kim Mingyu, 18 years old, just a couple weeks older than his girlfriend Nayeon is the son of Kim Minjae, who is the co-CEO of Samsung. He's an only child who lives with both of his parents and has the expectations of a perfect family, something that Nayeon's family doesn't have. Mingyu's parents treat Nayeon like a daughter and whenever she needs to part away from her father, she goes to Mingyu's home feeling welcomed everytime. Not only Mingyu is Nayeon's best friend and boyfriend, he's also her protector. He can sense the negative that comes from her father.