A young bourgeois man takes part in a hold-up, is arrested and sentenced. In prison, he discovers a world where only the strongest survive. He will come out transformed.

Born into a well-off family, Franz Blum had led a carefree youth until, some time after graduating from high school, he was arrested by the police. For, involved by a gang of bad boys, the young man had taken part in a bank robbery. A "heroic deed" which earned him six years in prison. Once behind bars, he was treated with ruthless inhumanity by the guards. And little by little - but inexorably - Franz turned into an insurgent...—Guy Bellinger