The novel is set during the 1943 Allied occupation of the fictional Italian coastal town of Adano (based on the real city of Licata). The main character, Major Victor Joppolo, is the temporary administrator of the town during the occupation, and is often referred to by the people of Adano as Mister Major. Joppolo is an idealistic Italian-American who wants to bring justice and compassion to Adano, which has been hardened by the authoritarian Fascist regime of Benito Mussolini.
When Major Joppolo arrives at Adano, he immediately asks the people of the town what they need the most. The first spokesman of the town tells Joppolo that they are in great need of food for some people have not eaten in days. The second spokesman of the town argues that the town's immediate necessity is a new bell. Joppolo is touched by the story of a 700-year-old bell that was taken away from the town by the Fascists. Mussolini had ordered that the bell be removed from the town and be melted to make weapons for the war. The people were greatly attached to the bell. To them, the bell was a source of pride and unity. Joppolo immediately sees the importance of the bell and makes persistent attempts to locate the bell.
In addition to finding the bell, Joppolo spends time trying to supply the town with food and other necessities. He soon discovers that the town has no fish because the fishermen have not gone out in months. When he speaks to Tomasino, the leader of the fishermen, Joppolo finds out that this is because the fisherman were forced to pay 'protection' money to the corrupt Fascist government simply to go out fishing. Joppolo tells Tomasino that he will not have to pay any bribes or extra taxes to the Americans for fishing. At first, Tomasino is convinced that Joppolo is lying to him and that it is some sort of cruel trick. Tomasino hates persons of authority because he believes that they are all power-hungry and corrupt. It takes extensive persuading and a visit to the authoritarian Lieutenant Livingston's office to convince Tomasino that Joppolo's intentions are good and that his only want is for the people of Adano to have fish.
Joppolo is faced with another problem in which he had to countermand the order of General Marvin in order to do what was best for the town. General Marvin is an army general who happens to pass through Adano. All day his armored car has been slowed down by mule carts that are blocking the road. Finally, on the road to Adano, he loses his temper and orders that his men shoot a mule that refuses move from the center of the road. When General Marvin arrived at Adano, he orders Major Joppolo to keep all mule carts out of the town. Joppolo is disheartened but complies with the order. Immediately, he calls for a meeting with all the officials of the town and tells them of the new order, but also that he is prepared to find a solution. The next day, Joppolo decides that countermanding General Marvin's order is more important than his own position as mayor of the town; therefore he tells the people of Adano that they may bring their carts into the town (among other things, the town has no source of water without the carts).
Later in the novel, Joppolo gains the admiration of Lieutenant Livingston, who invites Joppolo to come have a drink with some of his navy buddies. While there, Joppolo tells them of the town's need for a bell. Commander Robertson realizes that they might have exactly the bell that Adano needs, the USS Corelli. The arrival of the bell to the town coincides with a party that the town is hosting for Joppolo to express their gratitude for all of his great doings. Although the bell has arrived at the town, the engineers say that it will take them until the next morning to install it. At the same time Sergeant Borth, one of Major Joppolo's aides, finds a note from General Marvin that says that Joppolo has been relieved of duty as administrator of Adano because he countermanded General Marvin's order. Sergeant Borth tells Joppolo that he has been relieved from duty while they are at the party and hands Joppolo the order. The next morning, Joppolo leaves Adano, but does not say goodbye to anyone because he does not think he could. As the jeep is driving away, he tells the driver to stop for a moment. They hear the clear sound of a loud bell.