The story follows the last three days in the life of a retired United States Army officer in Venice, Italy.
In the period just after the Second World War, a fifty-year-old American colonel pays a visit to the site in Italy where he was nearly decapitated during World War I .
Cantwell (symbolic name) [explain why it is symbolic] is a skilled soldier, having risen steadily through the ranks in his thirty-year career and having personally killed 122 men (one of them using a nail driven through a two-by-four.) However, these achievements aroused the envy and mistrust of his seniors, who had reached their ranks mostly by political maneuvers rather than martial prowess. Needing a scapegoat, the military demoted him to the rank of colonel after he, following his orders, had led his brigade into an impossible battle in the Hurtgen Forest and lost a large portion of the brigade. After his demotion, he becomes bitter, and criticizes most of the Allied generals, especially Eisenhower, Leclerc, Patton, and Bernard Montgomery. He feels that they have subjected him to friendly fire in doing what their enemy had not been able to do to him.
Cantwell passes his holiday in Venice hunting ducks, eating, drinking, recounting his wartime exploits, and having a sexual relationship with a nineteen-year-old Italian Venetian contessa, Renata. Renata is Hemingway's highly idealized portrait of a nineteen-year-old Italian girl he encountered during his 1948 visit to Venice. She suggests to the general that they "stay at the Muehlebach hotel which has the biggest beds in the world and we'll pretend that we are oil millionaires."
His nostalgic liberty over, Colonel Cantwell proleptically anticipates his death by quoting the last words of rebel general Stonewall Jackson to his aide, and then crawls into the back seat of his staff car and dies of a heart attack.
Before his death, Cantwell gives orders for the return of some personal belongings to Venice, but his aide, angered by the colonel's criticism of his penmanship, decides to return the items "through channels", meaning that the honest colonel will still be the victim of politics even after his death.