Greece's Ionian Islands are Axis occupation of Greece by the Royal 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 Mountain Infantry Division Acqui, has a jovial personality and a passion for the mandolin, and trains his battery of men, (who have never fired a shot), to choir. 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.