Choi Sooyoung and Kim Taeyeon are bestfriends since 7 years old. They treat each other like they're sisters. They once meet and lived in America and has 2 childhood friends, Jinki and Kibum. When they reached 12 years old their parents decided to live in Seoul, Korea for business purposes. They left Jinki and Kibum but promised each other that they'll never forget their friendship. When they arrived in Seoul they meet their cousins, and they made their life a living hell. After 6 years they decided to live in one house and their parents agreed so they'll learn how to be independent. They met a guy that will be the reason for them to end their 12 years of friendship. Sooyoung went to Japan to move on, while Taeyeon broke up with the guy because she love her bestfriend than her boyfriend. A year later Sooyoung came back and fix their friendship. Jinki and Kibum went to Seoul to find Taeyeon and Sooyoung. They heal their broken hearts and marry them afterwards.