The antagonist of the novel, H.H. Holmes, is a psychopathic doctor, pharmacist, and serial killer from New Hampshire who comes to Chicago a few years before construction of the 1893 Chicago World’s Fair. In Chicago, Holmes uses his skills of manipulation, charm, and deceit to commit several crimes, including theft, insurance fraud, and murder. Holmes’s murdering comes to a halt in Philadelphia as his arrest for insurance fraud prompts deeper investigation into his past.