Un milione di italiani follows two young Neapolitan singers, Fatima and Sara, whose parents come from Senegal and Sri Lanka. Fatima is grappling with a love that doesn't want to end, and Sara is about to record her first disk. With a letter, the Italian government asks them if they want to become Italian citizens, one request that appears absurd given the profound belonging of the two girls to the context in which they live and were born. The two young women are called to sing live "Era de Maggio", a classic Neapolitan song, with the famous singer Maria Pia De Vito. And we find out what the dialect is their musical mother tongue.