Sanyi lives in a typical apartment complex in Seoul. Tired of being bullied at school, she finds little support from her distant mother Soyoon and her father, Chao, who struggles to survive as a Chinese immigrant. To escape her reality, Sanyi secretly observes her neighbors’ lives through their windows. One day, she witnesses a shocking crime through the window of her only friend, Hajin. As Sanyi grows closer to Hajin and his enigmatic mother Yumi, she finds herself torn between love and fear for Yumi. Eventually, Sanyi must decide whether to leave with them for North Korea.