Cinder by Marissa Meyer
From page one this book kicks arse and digs up an old fairy tale and plants it in a future far far away.
Earth is the grip of a plague, carried to the planet by illegal lunar folk. There is no cure and the emperor has succumbed. Long Live the new Emperor. The evil Lunar Queen is desperate to take over Earth and has spies working across the planet to aid her plan. Amongst this danger a cyborg grease monkey of considerable talent called Cinder, meets the handsome Prince Kai when he visits her shop to ask her to repair his android.
Life takes a downward turn when Cinder’s good step sister falls ill with the disease and Cinder is blamed by her evil step mother for her daughter’s ailment. As cyborgs are used as guinea pigs in the quest for a cure, she volunteers Cinder for trials. So far no Cyborg has survived testing but Cinder is immune. And the only other people known to be immune are lunar by birth. The mystery begins.
From here on the book rockets along a narrow old path and we are privy to her true identity, but Cinder has no idea of how important her immunity is going to become.