Sully is a rascally ne'er-do-well approaching retirement age. While he is pressing a worker's compensation suit for a bad knee, he secretly works for his nemesis, Carl, and flirts with Carl's young wife Toby. Sully's long- forgotten son and family have moved back to town, so Sully faces unfamiliar family responsibilities. Meanwhile, Sully's landlady's banker son plots to push through a new development and evict Sully from his mother's life.

Léon, the top hit man in New York, has earned a rep as an effective "cleaner". But when his next-door neighbors are wiped out by a loose-cannon DEA agent, he becomes the unwilling custodian of 12-year-old Mathilda. Before long, Mathilda's thoughts turn to revenge, and she considers following in Léon's footsteps.

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.