The trials and tribulations of a good guy who feels obliged to confess the truth to his wife or his boss every time he makes a mistake.

This certificate was formerly obtained by pupils at the end of primary school. The teacher of a small village has a dream: he wants his son to get his certificate and to be the best in the district ("Canton"). His younger son is less gifted: he is ashamed of him and treats him like a dunce. His obsession is so strong his marriage (his wife is a schoolteacher too) is soon on the rocks.