It tells the story of 10-year-old Doo Ri, who begins a new life in Musan with her mother following her parents’ divorce. She learns that she must know how to lie confidently in order to fit in a small society called school. Those in her surroundings, including her classmate and friend Min Ah, make efforts to shield her. Doo Ri and Min Ah even devise a plan to safeguard Doo Ri’s lies. Will the two girls be able to hide the lies from their classmates until the end?