Too young to fight, Thomas assumes a noble ancestry, adds a few extra years to his age, and becomes a soldier. In this guise, he meets the society star Princess de Bormes and her impressionable daughter Henriette. While the princess pursues charity work with the wounded, Henriette falls in love with Guillaume. However, Guillaume, resplendent in army uniform and issued with a shiny revolver, is lost like a child in a fantasy land of their own creation. At the novel's denouement, he clings to his imposture, but in mind, if not body, he has grasped the real meaning of war. This visionary novel is a "hymn to the cult of youth" in which World War I battlefields become an exaggerated spectacle where fiction and reality are inseparable.