[1] It is considered one of the earliest films belonging to the genre of Italian neorealism, due to its use of exterior scenes and the inclusion of non-professional actors.

The film's sets were designed by the art director Alberto Boccianti.

Its title refers to the Neapolitan song "’O sole mio".

Tito Gobbi stars as an Italian-American officer who is parachuted behind Axis lines to gather information on the movements of the German army and facilitate the allied landing.

In Naples he comes into contact with local resistance groups and ordinary citizens, who then join in the revolt against the German occupiers.