Frank Yakabuski is called to investigate a gruesome crime scene. A body has been left hanging from a schoolyard fence. On closer inspection, Yak finds a large diamond in the murder victim's mouth. Two criminal gangs -- the Shiners and the Travellers -- are fighting with each other, and Yakabuski turns to his father, a now-retired detective who has a long history with the gangs, for advice in the interrogation. Is the conflict over the murder of two men? The kidnapping of a little girl? Or, possibly, the diamond found in Augustus Morrissey's mouth? As if this weren't enough for one detective, a serial killer is taking a deadly road trip through the United States, heading towards the Northern Divide.