French nuclear tests irradiate an iguana into a giant monster that viciously attacks freighter ships in the Pacific Ocean. A team of experts, including Niko Tatopoulos, conclude that the oversized reptile is the culprit. Before long, the giant lizard is loose in Manhattan as the US military races to destroy the monster before it reproduces and it's spawn takes over the world.

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.