In 1946, Antonietta, an impoverished single mother, arranges for her son Amerigo to travel from Naples to northern Italy to live with a host family as part of the treni della felicità (trains of happiness) initiative organized by the Italian Communist Party (PCI) to transport poor southern Italian children to northern families who could support them in the years after World War II.

Amerigo refuses to go, but relents when he is caught by Antonietta's boyfriend fraudulently selling white-painted rats for furs.

The next day, Derna introduces Amerigo to her brother Alcide and his sons Revo, Lucio and Nario.

Later that night, Amerigo compares Derna with his mother, saying that Antonietta would not have let herself be treated that way before comforting her as she collapses into tears.

Amerigo is greeted coldly by his mother, who cynically tells him that he is ordained for a destitute life.

After some time, Amerigo, who is the only child not to receive messages and gifts from his fosters up north, visits the PCI offices and learns that his mother had kept Derna's packages from him.