Humanity pushed its way to the stars—and encountered the Gbaba, a ruthless alien race that nearly wiped us out. Earth and her colonies are now smoldering ruins, and the few survivors have fled to distant, Earth-like Safehold, to try to rebuild. But the Gbaba can detect the emissions of an industrial civilization, so the human rulers of Safehold have taken extraordinary measures: with mind control and hidden high technology, they've built