Paolo Bianchi, an average young man, picks up an underground newspaper on the street: he lives in northern Italy during the Nazi occupation and is mistaken for a communist, searched and beaten by the police. An influential friend manages to get him released, but now Paolo has a positive reputation among the partisans. To save him from further trouble, his friend gives him a document that corroborates his strong loyalty to the current regime: the safe passage he thus obtains helps, albeit inadvertently, the partisans on several occasions. Then the Allies arrive, accuse him of being a collaborator, and arrest him. His friend comes to his rescue.
