The series is set in a fictional world in which many near-omnipotent "divinities" once ruled over a large continent, imposing their whims on its peoples but also protecting them and allowing them to conquer and enslave the island nation of Saypur.
But after the Saypuri found a way to overthrow and kill the divinities, almost all of their miracles ceased to work and the continent was plunged into plague and chaos.
At the outset of the first novel, City of Stairs, the Saypuri republic, emerging as an industrial and military power from the ruins of the divine empire, is militarily occupying the continent.
In the second novel, City of Blades, set five years later, the war-weary Saypuri general Turyin Mulaghesh is pressured by her government to investigate the Continental city of Voortyashthan, where an insurgency against the Saypuri occupation is brewing amidst controversial efforts to reconstruct the Continent's economy.
[1] NPR considered the sequel to be the more accomplished novel for being less weighed down with exposition but no less rich or realized, and perhaps the better point of entry to the series.