A Casual Furlough in Paris ends abruptly for an Army CID investigator named Trot when he receives a secret command to arrest his leave-companion, Malley, for black-market operations. Trot fails; Malley eludes him and vanishes into the Mountmartre underworld—leaving Trot to return to his base in Germany and face an insinuation that threatens to wreck his career. From this point on, Sergeant Trot's safe and ordered world begins to disintegrate. Soon he finds himself, like Malley, a hunted man, and he, too, takes refuge in the crooked alleys of Paris, where he is caught up in a peculiarly corrupt and vicious racket. A victim and an outcast, scorned and humiliated by those on whom his lie depends, Trot seeks some means of saving himself and of protecting the French girl who has betrayed him. Stumbling on hints of a major criminal undertaking, he becomes all the more deeply involved in a world where the only morality is survival, and in which he is forced into a recognition of himself no longer simply as a soldier but as a man.