A forgotten promise. A cold case resurrected. A deadly conspiracy that will stop at nothing to keep its secrets buried. Sixteen years after a murder on Chicago's Green Line went unsolved, exiled detective Sam Laska returns to the city to confront the broken promise that has haunted him. As he delves into the dormant investigation, Laska discovers a former partner's suspicious death and narrowly escapes an attempt on his own life. With danger lurking around every corner, Laska must navigate a treacherous web of corruption and deceit to uncover the truth binding the two cases together. But powerful enemies are determined to keep their secrets buried at any cost.