Two female classmates from vastly different social backgrounds are struck by a mysterious magnetic force on a stormy night and switch souls. They agree to “live each other’s lives during the day and exchange diaries in the old library at midnight,” working together to keep up appearances. As they help each other navigate their respective social circles and relationships, they gradually discover that there is another side to each of their lives that no one knows about. And this body swap seems to be part of a carefully designed “experiment.”