The winter of 1893 brings much concern to those working to create the 1893 Chicago World's Fair on time. Cold winters bring a larger threat of fire, and Burnham's concern of fire grows. Ferris, despite the cold, begins construction on his wheel, encountering many issues along the way, despite his careful contracting of steel work and inspection of the parts as they come back to him. Additionally, Codman, the assistant Olmsted has left in charge in Chicago, falls ill and dies. Olmsted returns to Chicago unable to handle Codman's affairs as his grief overwhelms him; Olmsted falls ill again. He goes back home and sends another assistant, Rudolf Ulrich, to Chicago to do the work for the fair. Olmsted expresses distrust of Ulrich, feeling he lacks insight to do the job. Another big construction accident occurs at one of the larger buildings.
Although the optimistic tone of the previous chapters delivers hope that the task will be completed successfully, this chapter takes a different tone. More concerns over the construction of the fair arise, typical of sections and chapters that focus on Olmsted. One major purpose Olmsted's character serves in the novel is to help create suspense and worry.
Chapter 21 suggests that the fair might not be done in time for opening day. The newspaper's bleak prediction adds suspense, imparting a tug-of-war sensation.
The image of fire, often associated with Holmes, resurfaces in this chapter — a foreshadowing of something bad to come at the fair.