Sol, an obstetric nurse finds out, while pulling together files of newborn babies, that Professor Min and Mr. Park's babies have been switched by accident, and they have already checked out. Seven years later Seol is killed in a car accident, and her boss comes to know the fact while reading her diary. He informs the parents of this and tries to find the children their real parents in a way that will not hurt them. The boys, however, are too young to understand the situation. The two families decide to raise each other's boy as their own. Sometimes love that grows out of nurturing can be stronger than a blood bond.