In 1988, Duk-Sun (Hyeri), Jung-Hwan (Ryoo Joon-Yeol), Sun-Woo (Ko Gyung-Pyo) and Dong-Ryong (Lee Dong-Hwi) are high school students and Taek (Park Bo-Gum) is a go player. These five people have been friends since they were little kids. They all grew up together and are neighbors to this day. Their families are also very close to each other. They always hang around Taek's room and spend time together.