World peace is at stake if a spy-ring obtains the electronic device

The great fadista, Amelia Rodrigues, made her screen debut in Capas Negras, which took its name from the black capes worn by the students in the university city of Coimbra, where the film is set. The action begins in a tavern where a group of former students are reminiscing about their time at the university. One of the students, Jose Duarte then breaks into song, performing an impromptu fado in the local Coimbra style. The tavern owner's niece, the aptly named Maria Lisboa promptly retaliates with a fado of the Lisbon variety. The melodramatic plot then centers on the frustrated romance between these two characters, and the soundtrack is essentially a musical duel between these two different styles of Portugal's national song.

The legendary life of José Teixeira da Silva, José do Telhado, married to his cousin Aninhas, defeated his father's resistance, due to the fame of his heroism during the civil war.