I will call you! So you better answer your phone!

In the year 2020, a homestay is being conducted for male and female teenagers in preparation for a union between North Korea and South Korea. North Korean girl Ha-jin goes to South Korean boy Woo-yeong's house to homestay. Woo-yeong starts to bully Ha-jin who has taken his room, but alas! First love has found its way to these children. Woo-yeong runs away to Seoul with Ha-jin to help her meet her father.