The Ultrapolis is a city that dwarfs all other cities ever to exist. Not everyone who works in the Ultrapolis lives in the Ultrapolis, though. Many live just outside the Ultrapolis, in the Sticks. The Sticks has largely been abandoned by the Powers that Be. Police and rescue departments never much even enter the Sticks anymore. And that is where the Vigilantes step in, filling the void that the absence of the authorities has left, standing the line against crime and chaos through sheer force of will. That, and all of the mecha technology that a secret wealthy benefactor can buy.