Michael Kelly, a tough-talking Irish cop turned Private Investigator, is hired by an ex-flame to tail her abusive husband. But what looked like a bread-and-butter domestic dispute will turn out to be more than he bargained for. The tail leads him to an old house on Chicago's North Side. Here he finds a body and what looks like the answer to one of Chicago's most enduring mysteries: who started the Great Chicago Fire of 1871 and why. As he explores further he is drawn into a web of corruption and intrigue that reaches right to the top. The Mayor of Chicago is hiding secrets that date back to the Fire and beyond. Soon Kelly finds himself in the last place he wants to be - City Hall's fifth floor, where the Mayor is feeling the heat and looking to silence any investigations.