Lieutenant Frederic Henry (as yet unnamed) is the first-person narrator describing his experiences in the First World War as an American volunteer in the ambulance corps in the Italian army. It is late summer, and Henry and the other volunteers are living in a house in a small village on the Italian border. Below is a small, dry riverbed. As the troops move by, they raise up clouds of dust that cover everything. When the troops have passed, all that’s left is the bare road and the fallen leaves covered white with the dust. The plains, however, are rich with crops, portraying the fruitfulness of the countryside. Above them are the mountains, the Italian Alps where the fighting is. They are bare and brown as autumn approaches. In the nighttime, Henry sees flashes of artillery as the army battles for supremacy of the area. He observes that it is almost like summer lightning, but the night is cool and there is no feeling that a storm is coming (at least from the clouds).

In the middle of the night, Henry can hear the sound of the troops marching past, with guns pulled by tractors. Although it is the first modern, mechanized war, mules are used to carry boxes of ammunition while the men ride on motorized troop transports. Guns are also drawn by tractors, which are covered by canvas and branches as a means of camouflage. To the north is a mountain where there is also fighting. That mountain, however, is lost to the enemy.

As the dry, late summer changes to fall, the rains turn the roads into a mass of mud that covers everything. Leaves are stripped from the trees, leaving the tree-dotted plains blank and bare. The men, carrying ammunition in front of them under their capes, look like expectant mothers about to give birth any minute. As the small, gray motor cars pass, they splatter more mud than do the camions (a French word for trucks). Henry occasionally sees a small man seated between two taller generals, with only the top of his cap and his narrow back showing. He realizes it is the King of Italy, who is at that time living in Udine (a town in northeastern Italy, the site of the headquarters of the Italian High Command), going to the front to see how things are going (they are going badly). When winter sets in, cholera breaks out. Henry says that in the end “only” seven thousand soldiers die of the disease.