Josef "Schmutz" (german for "dirt"), a security guard obsessed with duty and cleanliness, is given the task of guarding a decommissioned industrial plant. While maintaining his devotion to the authority of property right, the self-proclaimed "Representative of Ownership" is himself slowly losing his sense of reality.

Un gardien de nuit, chargé de surveiller une vieille usine, devient fou. Son travail l'obsède, et l'amène à des actes de violence, jusqu'à commettre des meurtres.