Jin Eunwoo is a friend from childhood. You are neighbors and have always attended the same school from kindergarten to high school. You always tell Eunwoo all your feelings, and so does he. Sometimes you even go on double dates and you get to know Eunwoo's girlfriend well. The day your grandfather died, Eunwoo was always by your side. He always checks on your condition and makes sure you are okay. For Eunwoo, you are more than a friend. You are his sister and his family.