Diogo Alves is a Spanish fugitive that comes to the Portuguese capital terrorizing the inhabitants by his cut-throat methods against rich and poor people alike. He attacks the women launderers on the Lisbon Aqueduct and throws the bodies over the high wall, and assaults homes with his large band of criminals. Eventually arrested, he, his female companion and his henchmen are condemned to death by the court.

Nineteen-year-old Julio heads to Lisbon from the provinces and gets a job as a shoemaker for his uncle Raul. But when he meets Ilda, a confident young housemaid who becomes a regular shop visitor, his working-class values collide with the bourgeois trappings of modern life.

Leonel is a pianist, nostalgic of sweet melodies, while his son is the (real-life) leader of Os Gatos Pretos (black cats), a twist musical group. The conflict is eventu ally solved when Leonel's daughter, Cilinha, starts dating Raúl, a well-off young man, who promote a new dancing club, the Lisboa Antiga e Moderna, where old new music get even shares.