Cassie Klyne, nineteen years old, lives in the United States in the year 2015 -- but it's not our United States, and it's not our 2015. Cassie's world has been at peace since the Great Armistice of 1918. There was no World War II, no Great Depression. Poverty is declining, prosperity is increasing everywhere; social instability is rare. But Cassie knows the world isn't what it seems. Her parents were part of a group who gradually discovered the awful truth : that for decades -- back to the dawn of radio communications -- human progress has been interfered with, made more peaceful and benign, by an extraterrestrial entity.