Korea in year 1938. Joo-ran is a sickly girl who is transferred to the Gyeongseong Boarding School for ill girls. She is given a new name; Shizuko. At first life seems to be not different from other boarding schools. Joo-ran learns that before she came, another girl named Shizuko had suddenly left the school without saying goodbye to her friends. Soon after other girls in the class are reported to have gone home as well, after disappearing in odd circumstances. Now the young girl is confident, that there is something wrong about the Gyeongseong School. Joo-ran starts a risky research to uncover the secrets surrounding the school, which puts her life in danger.