I thought you liked me (1987)

On the way to summer camp, eleven-year-old Lena develops a crush on Wolfgang, but Antonia is interested in him too. Although Lena and Wolfgang grow closer to each other, camp director Eichler disapproves of their relationship and tries to split them up by assigning them to different groups. The conflicts escalate until one night, during a disco event, Lena suddenly runs away.