After losing their parents at a young age, Cortis became the head of the family. At only twenty-nine, he worked tirelessly to raise his younger siblings while building his own successful business. Despite living in a luxurious house, the family was anything but peaceful. The youngest, Kim Rae-lyn, was the family's little troublemaker. She argued with the twins—Keonho and Seonghyeon—almost every single day. From stealing food... To fighting over the TV remote... To throwing playful insults at each other. Their bickering never seemed to end. Meanwhile, James, Martin, and Juhoon usually watched the chaos from the living room, laughing because they knew the three of them loved each other more than they would ever admit. One rainy evening, Rae-lyn came home soaked after walking back from university. That night, she developed a high fever. Without saying a word, the twins stayed by her bedside. One checked her temperature. The other prepared medicine and changed the cold towels. They even took turns staying awake beside her until sunrise. Because no matter how loudly they argued... She would always be their little sister.