Re di Roma is a district of the capital where a woman, a mother of the family, lives in search of a student who rents a free room in her apartment.

Two people show up the same day to visit the house. They are of different social backgrounds: one is a doctor, a distinguished and respectable person, looking for a room for his newly enrolled daughter at university. The other, a young boy, is there for his sister.

The woman, attracted by the man, instead seems suspicious of the boy, initially frightened, then even annoyed by his presence.

Only at the end of the story will the reasons be understood.