After mistaking him for a masked killer, Jonathan fatally stabbed his sister's boyfriend on Halloween. One year later to the day, the siblings find themselves fighting for their lives against a very familiar masked murderer.

In cases ripped from the headlines, police investigate serious and often deadly crimes, weighing the evidence and questioning the suspects until someone is taken into custody. The district attorney's office then builds a case to convict the perpetrator by proving the person guilty beyond a reasonable doubt. Working together, these expert teams navigate all sides of the complex criminal justice system to make New York a safer place.

Ray Tango and Gabriel Cash are narcotics detectives who, while both being extremely successful, can't stand each other. Crime Lord Yves Perret, furious at the loss of income that Tango and Cash have caused him, frames the two for murder. Caught with the murder weapon on the scene of the crime, the two have no alibi. Thrown into prison with most of the criminals they helped convict, it appears that they are going to have to trust each other if they are to clear their names and catch the evil Perret.