The story takes place in Korea’s largest coastal city, Busan. By the mid-21st century, economic polarization becomes so exacerbated that the city is divided into the Lower Neighborhood (where inhabitants must live in fear of another tsunami that will sweep away their homes and loved ones) and the Upper Neighborhood (a world where haves look down upon the have-nots). An extremely dangerous form of time travel becomes possible, and Lower Neighborhood inhabitants are hired by Upper Neighborhood citizens to fetch nostalgic items from the past—for example, the secret to the broth of the “bone soup” of the title of this novel. Our main protagonist, Lee Uhwan, lives in the Lower Neighborhood and works at a dead-end job at a restaurant where he has reached his mid-forties without having accomplished anything or loving anyone. Then one day, he is tasked by the restaurant owner to bring back a shank bone and the method to bone soup broth. Uhwan makes it to the past and gets a job at a bone soup restaurant where he eventually learns that the owner is his grandfather, the owner’s son his father, and the son’s current girlfriend his future mother. But more importantly, working at the restaurant, Uhwan realizes just what it means to be part of a loving family. Uhwan, unwilling to let go of his family, decides to stay in the past. Trouble arises when it turns out there are many Lower Neighborhood errand runners from the future who are also unwilling to return to the future; they want to change events of the past so the future would turn out different. They attempt many acts of terrorism in the process, and Uhwan’s future father ends up being responsible for the deaths of many people when a plot goes awry in his attempt to save Uhwan’s life. Uhwan’s conscience does not allow him to stay in his past and make trouble for everyone, and returns to the future. The novel ends with him reuniting with his father, who has finally been released from his prison term.
