The story of a family who moves to a new suburban neighborhood during the summer holidays, with two daughters 10-year-old Laure and 6-year-old Jeanne. With her Jean Seberg haircut and tomboy ways, Laure is immediately mistaken for a boy by the local kids, and decides to pass herself off as 'Mikael', a boy different enough to catch the attention of the leader of the pack, Lisa, who becomes smitten. At home with her parents and girlie younger sister, she is Laure: hanging out with her new pals and girlfriend, she is Mikael. Finding resourceful ways to hide her true self, Laure takes advantage of her new identity, as if the end of the summer would never reveal her unsettling secret.