Cinder is a 16-year-old cyborg: a human embedded with synthetic parts. She is also the best licensed mechanic in New Beijing. To her knowledge, at the age of 11 she was involved in a hover accident that killed her parents and required extensive surgery to save her life. As a cyborg, she represents a class at the bottom of the social hierarchy, and therefore hides her synthetic parts with the help of work gloves and boots: “If Cinder’s body had ever been predisposed to femininity, it had been ruined by whatever the surgeons had done to her, leaving her with a stick-straight figure. Too angular. Too boyish. Too awkward with her heavy artificial leg” (34).

Cinder navigates life with an auditory interface that can adjust external noise levels, a retina display that communicates when people lie to her, and a connection to a net database of endless information. Adopted by Adri’s late husband, Garan, Cinder lives with Adri and stepsisters Pearl and Peony; she is accepted and loved only by Peony. Cinder becomes a key part in finding a cure and vaccine for the letumosis plague due to her natural immunity, an immunity that she learns is due to her Lunar nature.