Lee Somin and Choi Sooah were best friends since Pre-K. Their families had made them become friends due to the fathers, Lee Taehoon and Choi Jimin. They were the closest of friends and made it all the way into adulthood as best friends. They now hope to have their children become best friends. They both get married to their beautiful boyfriends from high school, Park Matthew, and Kim Minho. Now, since Somin got pregnant with twin boys, the best friends are planning a whole life for their children to become best friends. Especially when Sooah has her two baby girls only a year later. They decided their children will be best friends, and marry in the future. One small issue...the kids hate each other...