Matteo is a communist intellectual, the son of a wealthy bourgeois, who found himself blind from an eye after the war. One day in the streets of Rome he meets Amelia, a child suffocated by the bourgeois environment.
The love affair between Andrea, laborer from the italian northern area called Bassa Lombarda and apulian single mother, Rosaria, is grafted on the background of the inconveniences of poor commuters who must go to work in Milan by train.
