The Glass Republic

Teenager "Pen" Khan is burdened by a life of secrets, the biggest of which is now written on her face. Following a devastatingly close encounter with the Wire Mistress, Pen's face is strangely disfigured by dozens of crisscrossing scars, making her an outcast among her peers. The only person who understands and accepts her is Parva, Pen's mirror sister, confined to the world of London-Under-Glass.
Following Parva's abduction, Pen strikes a terrible bargain with the unforgiving Chemical Synod in exchange for the means to track her mirror sister down, and ventures into the unknown. In London-Under-Glass, appearance is everything, and Pen's peculiar scars make her a valuable ally. But some in the reflected city are doing everything they can to prevent Pen from learning the truth about the disappearance of a girl who shares her face.