The first part of the novel is primarily concerned with Dan Fuselli, an Army private in World War I, serving in the Medical Corps. Craving the prestige of promotion to corporal, Dan feels prepared to do whatever it takes to advance. Unprepared for the corruption he must accept from his comrades in arms, Dan overcomes his scruples and finally moves up, but must forfeit his other dream of marrying his sweetheart back home.

In Part 2, Chrisfield occupies center stage. A Midwestern farm boy, he rebels against military discipline, even pulling a knife on a sergeant. While marching with the troops, he is distressed to find a faceless German corpse. Increasingly emotional and resentful, he grows to hate the sergeant. Threatening his life leads to court martial, after which he makes good on the threat. After killing the sergeant, Chrisfield deserts and is left aimlessly wandering the forest.

His comrade Anderson occupies the third and final section. As an educated East Coast elite, he feels out of place among the other enlisted men. After he is wounded, he finagles an arrangement to let him study in Paris. Daydreaming over musical compositions helps pass the time until he meets Geneviève. Falling hard for the lovely Frenchwoman, Andrews goes AWOL, and is punished with a beating after he is caught. This time he decides to leave the Army for good, but when he reaches Geneviève, she is appalled by his cowardice and breaks up with him. Andrews rents a room and devotes himself to his musical compositions, but the landlady turns him in. As he is apprehended, the sheets of music go wafting out the window—his creative efforts were as futile as the war.