The film is loosely based on real life events of Marianna de Leyva, better known as "The Nun of Monza," whose story was made famous by the Alessandro Manzoni's novel The Betrothed.
Rome is on the thresh-hold of the Holy year 1925, the city wishes to present itself as 'spotless' to the outside world. The appearance of a child's corpse puts an end to these aspirations. The police arrest a small time crook who has committed a robbery but has nothing to do with the murder of the child.
Onoff is a famous writer, now a recluse. The Inspector is suspicious when Onoff is brought into the station one night, disoriented and suffering a kind of amnesia. In an isolated, rural police station, the Inspector tries to establish the events surrounding a killing, to reach a startling resolution.