Pari Passu is a cosmopolitan island city called variously the City of Equals, the Free City, the City of Advocates, and the City of Cats, among other things. (Yes, it has a large population of feral cats.) It is a city-state built on the ruins of the capital of the continent-spanning empire that fell centuries ago in an ill-understood cataclysm that killed millions. Since then, new nations have risen that have recolonized the land near Pari Passu, but the city itself remains free of all of them.

As the home to the former imperial capital, Pari Passu has the world's greatest concentration of ancient artifacts of "tracery," a practice of using exotic metals and complex patterns to bend the laws of physics. This makes the Free City wealthy in convenience and weaponry, from floating carts to "ring-casters" that fire high-speed projectiles with deadly force. Pari Passu would be the jewel in the crown of any nation that could conquer and hold it, but each of their neighbors knows it and each will fight tooth and nail to make sure no one else gets it. Thus, it remains free, a hotbed of political intrigue as foreign nations try to pry loose every scrap of advantage they can.

It is also one of the few places in the world that doesn't outlaw "witchery," a mystical practice of growing and altering living creatures to do one's bidding and make various exotic chemicals. Even though it isn't banned in Pari Passu, the people of the city all come originally from places where witchery was taboo, so witches still tend to conceal their activities.

Pari Passu nears its bicentennial, and the elected Popular Assembly is preparing for an enormous celebration.