Carmen is twelve years old and is spending the summer holidays in town with her mother, who is growing more and more confused. Due to a lack of playmates her age, she plays with two younger children. Their games are disturbed by a teenager, Bengt-Olof, nicknamed Bengbulan, who terrorises and scares them. Carmen’s mother becomes acutely psychotic and leaves Carmen alone, with no other grown-ups around to help her. When the adult world lets them down, the children have to band together and take matters into their own hands.