Larson introduces two unnamed main characters and compares them. Both men are good-looking and unusually skilled. One is an architect, the other a murderer. Ultimately, the ensuing story is about the struggle between good and evil, and why some people choose to do great things for the world while others decide to cause sadness.
Both men are linked by a single event that proves nearly as important and historically altering to America as the Civil War. Larson mentions that the book is non-fiction and anything in quotation marks comes from a written document. The setting is mainly Chicago, but occasionally switches to other states.
Larson includes two quotes before the prologue. The first quote is from Daniel H. Burnham, the Director of Works for the World’s Columbian Exposition of 1893. Burnham admonishes not to make “little plans,” because only big plans possess the magic to incite great emotion. The second quote is from H. H. Holmes. He states that he was born with the devil inside him and has no choice in being a murderer.
The prologue is set on April 14, 1912, and introduces the famous architect Daniel Hudson Burnham, who is sixty-five years old. He cruises with his family on the opulent Olympic ship. His severe foot pain keeps him confined to his room. Burnham chose the Olympic for its grandeur and record as the largest passenger vessel in service. Right before he departs on his trip, a sister ship claims that title. Burnham starts to think about his friend, the painter Francis “Frank” Millet, who is currently on the sister ship. Burnham tries to send him a telegram, but the messenger returns and says the operator will not accept it.
Larson switches to Burnham’s memory of the 1893 Chicago World’s Fair, officially the World’s Columbian Exposition and nicknamed the White City. Celebrating the 400th anniversary of Columbus’ discovery of America, it ran for six months. Burnham and Millet became close friends as they worked together to realize the Fair as chief architect and chief painter. Despite many impediments, Burnham and his architects created a wonderland of enormous buildings, lagoons, and access to new and exotic entertainment. The Fair attracted important innovators and societal authorities, and introduced lasting products and concepts.
The Fair also incited tragedy. Many workers were killed and injured during construction, fire killed even more, and one assassin ruined the closing ceremony. Young, newly independent women drawn to Chicago by the Fair disappeared. Slowly, as letters arrived from worried parents, it became apparent that they were all last seen at a particular building. A man in the shadows came to call himself the Devil.