Grace Travis (Thandie Newton) is an undercover detective, torn between her identity as a loving mother and her cold, calculating persona as an agent for the crime boss Jimmy Laszlo (Marton Csokas). Tormented by her son's unsolved murder, Grace conducts her own investigation, convinced that the killer lies somewhere within Jimmy's treacherous ranks. Now, in order to uncover the truth and stay alive, Grace must help Jimmy weed out the traitor in his midst.