[3] The Interdependency is a thousand-year-old human empire of 48 star systems connected by the Flow, a network of "streams" allowing faster-than-light travel.

As a natural phenomenon, the Flow is poorly understood; Earth disconnected from the network thousands of years ago, and civilization on another system collapsed more recently when its pathway suddenly closed.

The trading houses are incredibly wealthy from government-sanctioned monopolies and by collecting tolls at "shoals", entrances and exits to Flow pathways.

The house covertly supports rebels on End to overthrow its duke, hoping to take power and become the new royal family when the Flow network reshapes.

Other nobles and bureaucrats are skeptical of their civilization's coming collapse, and Nohamapetan controls the Flow exit and imperial troops at End.