The ambulances join the rainy retreat on the packed roads and soon the column comes to a standstill. Frederic walks ahead to find that the road is backed up for as far as he can see. He returns to the ambulance to find Piani asleep. Frederic sleeps as well. They awake when the truck in front of them starts to move. Soon thereafter the column comes to a stop again. He walks back to find that Bonello has picked up two sergeants of engineers who have become separated from their group and he gives permission for them to ride. In Aymo's ambulance he finds two young girls scared out of their wits that Aymo will try to rape them but unwilling to leave the relative safety of the car. They eat some cheese and when Aymo learns that they are virgins he reassures them of their safety and they seem relieved. Frederic returns to his ambulance and comforts himself by dreaming of Catherine.
At 3:00 AM, Frederic reaches for the wine and admits to himself that if they ever hope to reach the fall back positions in Udine, they will have to leave the main road that is now hopelessly clogged with peasants and military vehicles and horses. He locates a side road and tells Bonello to keep the two engineers in his car because they might be needed to push. The two girls remain in Aymo's vehicle though they will not be good for help. The road leads to an abandoned farmhouse and they breakfast on foraged wine, cheese and apples. It becomes clear that the sergeants dislike the drivers. Before they leave, Bonello fills their canteens with wine from a large jug. They get back in the cars and follow the road past the house.
They take many secondary roads and draw about ten kilometers away from Udine when at noon Aymo's car becomes stuck in the mud. They hear the sound of planes bombing the main road. The two sergeants refuse to help and begin to walk away. They ignore Frederic's command to return and he fires on them and hits one of them, the other escapes. Bonello eagerly asks to be allowed to finish off the wounded man and does so using Frederic's pistol. After repeated attempts they cannot free the stranded car and decide to abandon it. The other two vehicles become mired in the muddy field and they start for Udine on foot. Frederic gives the frightened girls money and tells them to go to the main highway and find someone to take care of them. They walk fast for fear of being overtaken by the advancing Austrian army and, Frederic believes, for fear that he will take the money back.
Frederic and the drivers come to a river bridge lined with abandoned vehicles. Frederic climbs up to the bridge and looking at a bridge further down the river sees a staff car passing and recognizes German helmets on the passengers. In a few moments a troop of German bicycle soldiers passes on the other bridge. Frederic is very angry because seemingly no attempt has been made to stop the advance. They cross the bridge and follow railroad tracks across a flat plain. On the way they hear firing and see more German troops. When they try to leave the track and start across the field, Aymo is shot and killed by what they believe to be skittish Italian soldiers. Frederic, Bonello and Piani decide to hide until nightfall in an abandoned barn. Frederic lays down in the hay and begins to daydream about his childhood shooting sparrows. He dreams of Catherine. Piani returns with foraged goods and explains that Bonello has left to become a prisoner.
That night Piani and Frederic walk until they reach the main column of the retreat and Frederic muses that it was silly for Bonello to leave because he and Piani made it past both armies safely. Aymo's death had been sudden and random and impossible to avoid. Piani and Frederic join the retreat and walk throughout the night. Frederic assures Piani he won't report Bonello for desertion and as they walk they observe other soldiers calling for peace and throwing away their rifles. Piani says that he will no longer refer to Frederic as Tenente because some of the troops have been shooting officers. At daylight they reach the rain-swollen Tagliamento River. They join the crowd joylessly crossing over the wooden bridge and at they far side they encounter some officers and military police [carabinieri] pulling officers from the column. One of the police grabs Frederic and he resists but to no avail. He observes that the officers being questioned are then mercilessly shot and he runs for the river and dives into the cold water.
Frederic holds onto a piece of heavy lumber and succeeds in floating down river far enough to escape the soldier's guns. After a struggle to avoid drowning he manages to drag himself ashore. He removes his clothing and squeezes the water from it before putting it back on. He counts his wet money and finds that he has three thousand lire. He removes the officer's insignia from his sleeve and spends the day making his way across the Venetian plain until he reaches a railway where he waits. Finally a train comes down the track and he eludes the soldiers at a nearby bridge and manages to jump onto one of the passing freight cars. He quickly ducks under a canvas tarp covering some artillery guns immediately hits his head on a piece of equipment and feels blood coming from the wound. He knows the train is going to the town of Mestre and he resolves to get off before the train reaches the city limits. He is very hungry.
Lying on the floor of the freight car, Frederic thinks about his knee and decides that it has held up very well. He begins to think of Catherine but decides that until he is sure he will see her again it is best not to think of her. He realizes that he no longer feels any obligation to the Italian army. "I was not against them,' he muses, "I was through." He knows that Piani will report him as shot or drowned and he has no immediate concern except to reach Mestre and eat. He realizes that he will never see Rinaldi or the priest again because "that life was over." He thinks about where he will go with Catherine when they are reunited.
In this section Frederic comes to believe that the war is hopeless. The part that Frederic and his drivers play in the retreat becomes progressively more ridiculous and hopeless. The ambulances and their cargo are lost to the mud and Frederic shoots an Italian because the man will not obey an order and scared Italian soldiers shoot Aymo. Increasingly Frederic's thoughts turn to Catherine during this portion of the story. His separation from the Italian cause is made complete when he realizes that the Italians will shoot him simply because he is an officer and the army is retreating. Earlier he had expressed his theory that a war cannot be won in the mountains and after seeing the evidence first hand, he resolves to make a separate peace. For the second time in the story he goes to Mestre on a train. This time, however, instead of riding inside drinking purchased grappa, he arrives under a tarp with a bleeding head and an empty stomach, a fugitive from the army, and in danger of being executed. He has fully shed his old life and embraced his future with Catherine and it is toward that goal that he now struggles.