Guest is an ordinary college student in modern society. Driven by a sense of justice, they try to stop someone from jumping into the Han River. However, the struggling person causes Guest to fall in instead. As they sink into the depths, they are sucked into a mysterious glowing object and lose consciousness. When they open their eyes, they see a landscape that is familiar yet strange. The forest of city buildings is gone, replaced by thatched-roof cottages and tiled houses. While Guest is still dazed and trying to gather their senses, a woman comes running from a distance and trips over a rock.