A quiet, solitary man, Olivier is a carpentry teacher in a reformatory where juvenile delinquents undergo social rehabilitation. The arrival of a new student, Francis Thirion, 16, makes the teacher uneasy. The teenager tells Olivier that he would like to join his carpentry workshop, and although Olivier at refuses his request, he finally gives in and lets Francis join the group. Gradually, an ambiguous relationship develops between the teacher and student, and the young apprentice asks Oliver if he can become his tutor. One day when they are alone, Olivier badgers Francis with questions and makes a disconcerting revelation.