Aremis Slake lives in a room underground in the subway station Grand Central – 42nd Street. It soon becomes the home he has never known. He collects used newspapers off passing trains and makes a living selling them. He has two regular customers: the cleaning lady, and a man with a turban. A major theme throughout the book is Slake's low self-esteem and lack of experiences with empathy, which are dealt with throughout the course of the book.
With the money that he gets from doing this, he buys food from the local diner, and soon becomes a regular customer. The people at the luncheonette see him there every day and have sympathy for this homeless boy. They offer him a sweeping job and pay him with food sufficient to meet his needs. Also, whatever he finds on the floor he gets to keep, so Slake eventually has quite a collection of various items he's organized and used to decorate his cave.
There are also occasionally sections of the book entitled "On Another Track", about the parallel life of a man named Willis Joe Whinny.
Willis Joe is a middle-class motor man who also has an internal dilemma. He conducts trains with the depressing mindset that people are like sheep, lacking the empathy essential for psychological health.
At the climax of the book, Willis Joe meets Slake and their paths coincide due to a railway accident that was thought to have been caused by holes in the subway walls. Terrified, Slake scrambles on the subway track because he has pneumonia and needs help, because his home was doomed to be sealed up due to repairs needed in the subway. He scrambles onto the track with a sign that says STOP and Willis Joe saves him, stopping the train with a determination he had not experienced for years.
When Slake awakes in a hospital, he decides to flee for the rooftops. He sees his symbolic bird fly away, ending a miserable period in his life and signifying depression.
He then departs with renewed hopes and purposes.
