"A Million Open Doors" introduced the universe of the Thousand Cultures--in which, a 1,000 years hence, humanity's hundreds of settles worlds are finally coming back into regular contact with one another via the recently invented "springer", which affords instantaneous travel between worlds separated by light years. In his new novel, set 12 years later, Giraut and Margaret have the important task of bringing into the community the one human world that has yet to build a springer--the hostile world of Briand.