Seventeen-year-old Alex Binary doesn't know if she should stay a girl, or appease her best friend Logan and change back into a boy. In the virtual world of Cinder, all minds must choose an identity on their eighteenth birthday. Blonde hair or black, tall or short, boy or girl. For the citizens of Cinder, the decision is crucial. Unfortunately for Alex, it's a decision she may never be able to make. Zeus, a psychopathic artificial intelligence, seeks godhood through the destruction of the virtual worlds. To save them, Alex braves reality and joins forces with a group of rebel A.I.'s intent on defeating the unhinged machine. Along the way, she struggles with concepts of gender, identity, and what it means to be truly human in a world run by programs.