Greece's Ionian Islands are occupied by the Italian Army when it brings a large garrison along with a few Germans to the tranquil island of Cephalonia, whose inhabitants surrender immediately. Captain Antonio Corelli, an officer of the Italian 33rd Acqui Infantry Division, has a jovial personality and a passion for the mandolin, and trains his battery of men (who have never fired a shot) to choral sing. Initially he alienates a number of villagers, including Pelagia, the daughter of the village doctor. She is an educated and strong-willed woman. At first offended by the Italian soldier's behaviour, she slowly warms to Corelli's charm, and mandolin playing, as they are forced to share her father's home after the doctor agrees to put him up in exchange for medical supplies.