Cinder: Book One of the Lunar Chronicles by Marissa Meyer
I had earlier read the second and third books in the Lunar Chronicles series and did not care for them much. This one did seem much better. It is a "Cinderella" story, set in a futuristic earth. Lunar people have special powers, but also carry a disease to which they have immunity that is deadly for earthlings. Cinder is the Cinderella character who lives with her cruel guardian and her daughters. She is a cyborg human who had suffered a bad accident when she was long and had many parts replaced. She can't remember any pre-Cyborg life. She works in android repair. The prince comes in to have one of his androids repaired. She does a great job and the prince falls for her, but she rejects his overtures. Her guardian mother has no desire to support her and is glad to enroll her in a trial to help cure the disease. There she discovers that she has immunity and later learns more - she is actually Lunarian. The prince's dad has died and the prince is set to be ruler. The Lunar queen has come to take his hand in marriage. However, he really likes Cinder. Meanwhile Cinder escapes from her family, but discovers the Queen's evil plot and saves the kingdom, but has to spill her state has a Lunar Cyborg to the prince. She also later finds that she is royalty. The story is told in a quick moving, light tone.