In the book's prologue, Leo Colston chances upon a diary from 1900, the year of his thirteenth birthday, and gradually pieces together a memory that he has suppressed. Under its influence, and from the viewpoint of what he has become by the midpoint of "this hideous century", Leo relives the events of what had once seemed to him its hopeful beginning. The importance of his boarding school's social rules is another theme running through the book and complicates Leo's interaction with the adult world.