It is fall and Frederic observes that the village of Gorizi is gloomy and more damaged by the war than when he left in the spring. He sees the major who is friendly but has become disillusioned now that the war has turned against the Italians. He asks if Frederic has received his decorations and Frederic tells him that he has. He instructs Frederic to go the Bainsizza the next day and take command of four ambulances working in the mountains there. Frederic returns to his room and while he waits for Rinaldi, he thinks about Catherine. Rinaldi returns and although he is happy to see Frederic, he is depressed by the war. He inspects Frederic's knee and insists that more physical therapy should have been done but Frederic insists that it is better. Rinaldi chides Frederic for having returned too serious and though Frederic is recovering from the jaundice, he agrees to have some cognac. While they drink, Rinaldi asks about Miss Barkley and Frederic admits that he is in love. Rinaldi tries to make light of the affair but when Frederic tells him to stop if he wants to continue being his friend, Rianaldi relents. Rinaldi somberly reflects that only drinking, whoring, and his work bring him pleasure anymore and Frederic and he reaffirm their friendship.
At the mess that night it is only Frederic, Rinaldi and the major. The priest joins them halfway through the meal and is pleased to see Frederic. Rinaldi grows more drunk and despondent and after unsuccessfully trying to bait the priest he begins to talk of having syphilis. Rinaldi leaves and the major explains to Frederic that Rinaldi has been working very hard and the major does not believe he has syphilis. He also mentions that there is talk of an Austrian offensive before winter but he doesn't believe it will happen.
The priest and Frederic return to Frederic's room and the priest talks of how the soldiers have begun to change and become gentle and complacent since the war has intensified. The priest believes the war will end soon but Frederic expresses doubts. Both men agree that neither has faith in victory or defeat any longer. The priest sees that Frederic is very tired and after they both affirm their enjoyment in talking to one another the priest leaves.
Early the next morning Frederic travels to the mountain village where the ambulances are stationed. He notes that it is odd to travel past the point where the previous spring he had been wounded. The village is badly damaged from the fighting but is well organized and he has no trouble locating his ambulances. Gino, the man he relieves, has also heard rumors of an impending attack, both by the Italians and the Austrians, but he believes neither rumor. They discuss the difficulty of holding the position if the Austrians do launch an attack. Frederic posits his theory that a war cannot be fought in the mountains but admits that since that is where they are fighting, he has not come up with a better idea. Frederic muses that abstract terms such as "honor" and "sacrifice" have come to mean little to him.
That night there is much artillery shelling and probing of the lines. The ambulances make several runs with the wounded and the rain turns to snow and then back to rain. The troops hear that the Austrians have broken through the Italian lines to the north but this report is officially denied though nobody, including the officers, knows what to believe. Frederic learns that if there is to be a retreat, the wounded are to be left behind and the ambulances are to be used to evacuate hospital equipment. The next night the retreat starts. It is an orderly and sullen affair in the rain. When they reach Gorizia the town is being evacuated and Federic and one of the drivers named Bonello converse about the girls from the bordello being loaded into an army truck. Frederic finds a note commanding him to load the hospital equipment into the ambulances for the retreat. The other two ambulances arrive and one of the drivers, Piani is exhausted and can think of nothing but sleep. Frederic offers to help the other driver Aymo change the oil and grease the cars but Ayamo insists that he does not need the help. They load the three ambulances with equipment and then they sleep for a few hours. Aymo makes pasta asciutta and they wash down the meal with two bottles of wine from the cellar. Frederic agrees to ride with Piani so he won't fall back asleep. When they leave they take two more bottles of wine and some cheese for the journey.
Frederic witnesses the changes in his friends and begins to understand the deleterious psychological effects of the worsening military situation. Rinaldi has become cynical and morose in his drinking and tortured by the thought syphilis. The priest has gained some confidence but is tired and serious. The talk is now of how to end the war and which side will capitulate first. The men have become cowed from living with death everyday. Frederic returns to duty as an officer in charge of ambulances but even as he goes through the motions of his duty, he realizes that the concepts he sought before his injury, things like "honor" and "duty", mean nothing to him. The summer with Catherine has given his life a new direction and his role in the army is part of an old existence that no longer compels him. He does his duty, however, and organizes his small group for the retreat.