Twin brothers Baek Do Ha and Baek Do Yeong were separated by their parents’ divorce at a young age—Do Ha grew up in the United States, while Do Yeong remained in South Korea. Every summer, Do Ha returns to Korea to spend 21 days at his father’s duplex home, reuniting with his brother and their neighbor, Song Ha Gyeong.
Ha Gyeong’s father is close friends with the twins’ father, and over the years, she and Do Ha form a complicated bond. What begins as playful teasing between childhood friends slowly blossoms into unspoken affection—but Do Ha’s brief annual visits make it impossible for her to confess her feelings.