When life throws you curveballs, the way you react to it and live your life defines the person that you are. Lee Young Shin (Gong Hyo Jin) certainly doesn't have an easy life. She is a single mom raising her 8-year-old daughter, Bom (Seo Shin Ae), while taking care of her senile grandfather (Shin Goo), who is always wandering off. Bom is HIV-positive, but Young Shin makes a game of teaching her to manage her condition without her knowing about it while also keeping it a secret from the small island community of Pureun-do ("Blue Island").