Meet Detective David Gold. He's a third generation native of hardscrabble South Chicago. He's also one of Chicago's most decorated homicide detectives. Meet Gold's new partner, Detective AC Battle. He's a native of Mississippi whose family moved to Chicago to escape the Jim Crow South. He grew up in the Robert Taylor Homes, the penal colony of high rises across the Dan Ryan Expressway from Mayor Daley's house and Comiskey Park. Here's their first challenge. More than a decade after 9/11, someone is setting off fire bombs in Chicago using untraceable cell phones. An unknown group takes credit for the bombings and demands the release of Hassan Al-Shahid, a University of Chicago graduate student whose plan to set off a bomb at the Art Institute was thwarted at the last minute by Gold and his long-time partner, Paul Liszewski. Their heroic efforts had cost Liszewski his life and put Gold in the hospital. Shocked and grieving, Gold rallies to receive a Medal of Valor on the steps of that same Art Institute. During the ceremony, a car bomb explodes across the street and moment later Gold receives a text: It isn't over. The FBI and Homeland Security believe the new bomber is a lone wolf. That makes him even more dangerous. More car bombs are detonated at the Wrigley Field El station, Millennium Park, the Museum of Science and Industry, O'Hare Airport, the Hyde Park train station, and the upscale Rush Street area near North Michigan Avenue. The bomber has shut down a major US city. Just to free Al-Shahid? Gold and Battle hunt him across Chicago's colorful neighborhoods: from the high rises of the Magnificent Mile to century-old churches where mass is still celebrated in Polish to the ivy-covered buildings at the University of Chicago to crumbling old synagogues and gritty seafood shacks next to the ghostly expanses of vacant land where the steel mills once stood.