The film is based on a series of immensely popular Swedish children's books, about the boy Bert, who is just hitting puberty and having the usual problems with it. But that's where the usual ends abruptly.
17 years old Lina goes to the Arvika Festival with her boyfriend Calle despite that her mother forbade her. At the festival she meets the singer Marc and they start to like each other but things are getting difficult.
