Eighteen-year-old Brazilian Cora and grandmother Lucia visit ancestral home in Puglia, Italy. Land sale delayed due to town's music festival. Family tensions resurface as Cora grieves father's death, encounters his idol Marcelo Bianchini.

Duetto takes place in 1965 and tells the story of 18-year-old Cora, a Brazilian from an Italian family who, after losing her dad in a tragic car accident, goes with her grandmother Lucia to Puglia, Italy, where her ancestral homestead still stands. Lucia, aiming to sell an old family land lot, reencounters her sister Sofia and her husband Gino, whom she hasn't spoken to in 40 years. Things get complicated when the sale of the land turns out to be lost in bureaucracy and takes more time than they expected because of the town's upcoming traditional Music Festival where the biggest Italian musicians of the time perform. Lucia and Cora are forced to extend their stay and old family issues resurface, creating for Cora an intense journey of grief and growth, along with the unexpected, almost fantastical encounter between the girl and Marcelo Bianchini, the Italian "cantautore" who was an idol of her deceased father.