People like "Chicago Fire," people like it a whole lot. NBC is betting that what folks like about "Chicago Fire" is the drama, the location, and the notion of emergency services in general. They are also betting that it isn't the fire aspect in particular of the whole thing that has people enthralled. How do we know this? Because tonight they are launching a "Chicago Fire" spin-off that will feature Chicago and drama and emergency services, but not fire. Instead of fire, we're going to get crimes as this new series is called "Chicago P.D." Of course, fire can also be a crime, but isn't always one. Crime is always a crime.