In 1925, young Florentine typographer Mario moves to via del Corno to be near his girlfriend Bianca. Here befriends Maciste, his landlord, and Ugo, anti-fascists both of them. After a resident is beaten by the fascists, Mario meets the wife Milena at the hospital, falling in love with her and leaving Bianca. Maciste is killed, again by fascists, while Ugo is wounded and he seeks shelter in a nearby house. Here he falls in love with Gesuina and the two marry. Milena's husband dies, but she and Mario part ways. Later, Mario is arrested by the police.

During the winter of 1944, the partisans stationed in the Ligurian Apennines must go to a factory in Genoa, in order to pick up a delivery of weapons. Meanwhile, there's a strike in the city and the Nazis are trying to suppress it violently. The factory becomes the scene of fighting between the Germans and the partisans but the latter, aided by the workers, will be able to get the better.