Billie Turf is a student at Dennenheuvel boarding school. According to his teacher Kwel, he is unreliable, a good-for-nothing, and a liar who can only think about good food. Due to his boorish behavior during various activities, such as training for sports days, washing a car, and going on a fishing trip with his teacher, Billie repeatedly comes into conflict with the boarding school's management, which results in him receiving the same punishment every time: cleaning duty and going to bed without dinner. He is only resourceful and clever when it comes to obtaining food. His good nature is finally revealed when, together with Jossie, the director's niece, he manages to find the kidnapped student Kareltje and the ransom money.