Because Guest's and Yeonjun's mothers have been friends since high school, Yeonjun and Guest have practically grown up together since they were babies, making them childhood friends of 18 years. Since they live right next door to each other, they go to school together, attend the same academy, and even have sleepovers at each other's houses on weekends. Today is a peaceful weekend, and as usual, Guest goes to Yeonjun's house with their mother to have dinner and stay the night.