At 21, Eddie Keegan becomes a probationary fireman and begins 3 months of intensive training on Welfare Island. Eddie's major purpose is to live down a trauma which has haunted him since the age of 6 when he was accused of setting fire to the tenement he lived in. As he learns to climb a ladder, distinguish various tools, and acquires the special firemanic language, Eddie also reads books about fire bugs and pyromaniacs. He learns, as does the reader, that pyromaniacs ""have baffled psychologists , alienists, and psychiatrists for years because of their inscrutability."" Eddie's home life is made miserable by a father who: still believes Eddie set the fire and doubts the existence of the ""strange little man with one eye""; who looks up to the big guys with money and ridicules Eddie for taking such a stupid job; and who blows his Irish top when Eddie brings home his only friends, a Negro couple, for a graduation celebration. Eventually Eddie captures the little man of his nightmares, is interviewed on TV, and is up for a citation before he's served out his six month's trial period. Despite the melodramatic ending, the book makes it clear that being a fireman is no glory job and its appeal will be to boys fascinated by the technology of modern fire fighting.