A woman is shot as she waits for her train to work. An hour later, a second woman is killed as she rides an elevated train through the Loop. Then, a church becomes the target of a chemical weapons attack. The city of Chicago is under siege, and Michael Kelly, former cop turned private investigator, happens to be on the scene when all hell breaks loose.  Kelly's brassy investigating and razor-sharp instincts lead him into an intricate plot involving a retired cop, a shady train company, and a quietly ticking weapon nestled deep in the city's underbelly.  But when his girlfriend--the gorgeous judge Rachel Swenson--is abducted, Kelly realizes that the only way he's going to find the killer is to excavate his own stormy past.