Pacific Rim meets The Handmaid's Tale in this blend of Chinese history and mecha science fiction for YA readers. The boys of Huaxia dream of pairing up with girls to pilot Chrysalises, giant transforming robots that can battle the mecha aliens that lurk beyond the Great Wall. It doesn't matter that the girls often die from the mental strain. When 18-year-old Zetian offers herself up as a concubine-pilot, it's to assassinate the ace male pilot responsible for her sister's death. But she gets her vengeance in a way nobody expected—she kills him through the psychic link between pilots and emerges from the cockpit unscathed. She is labeled an Iron Widow, a much-feared and much-silenced kind of female pilot who can sacrifice boys to power up Chrysalises instead.​