Matt Scudder (Liam Neeson), formerly part of the NYPD, now works as an unlicensed private detective. His latest client is a drug trafficker (Dan Stevens) whose wife was kidnapped and brutally murdered, and as Scudder delves deeper, he finds that the crime's sequence is the modus operandi of the perpetrators. Before they can strike again and destroy other lives, Scudder races through the back streets of New York to catch the killers, blurring the lines between lawful and criminal as he goes.