Grace is a morally and emotionally-conflicted undercover detective who is tormented by the possibility that her own actions caused her young son's mysterious death. In her quest for the truth, Grace goes rogue and falls deeper into a forbidden relationship with Jimmy Laszlo, head of the city's most powerful and dangerous crime family. To stay alive, Grace must help Jimmy find the traitor in his midst, while knowing he may have played a role in her own tragedy.