If twelve-year-old Karl had been able to choose who he fell in love with, it probably wouldn't have been the much taller Lea. The fact that Lea is about to change schools doesn't make things any easier. 'Different school, different boys!' says Karl's older brother Tom, and advises him to be brave for once. Karl invites Lea into his improvised bathroom laboratory. Taking and developing photos has been Karl's favorite pastime for years. Lea is impressed by Karl's 'light magic' in the lab, but time is running out for further meetings. Karl only has one last chance to become Lea's boyfriend during the upcoming school trip. During this project week, the class shoots a film entitled "In love". And suddenly it becomes clear that Karl is not alone with his problem.