Chicago is a city in the state of Illinois, the United States of America.
In 2027, Chicago is one of several american "fortress cities", under heavy enforcement due to the spiral of economic and civil unrest, rising terrorism, draconian governance and subsequent dissent in the United States.
In 2072, The city is Alex Denton and Billie Adams' hometown, and the site of the Chicago Tarsus Academy. That year, one day, at 5:15 AM, a nanite detonator is activated by a Knights Templar terrorist near the Tarsus Academy, destroying most of the inner city and killing everyone in range. Some people are able to evacuate Chicago by airborne transport. For instance, Alex Denton and Billie Adams are relocated to Seattle by helicopters.
New Chicago is the WTO enclave part of the city of Chicago. It is the area where the Chicago Tarsus Academy resides in, and hence the "ground zero" of the nanite detonation.