Mirror's Edge (Impostors, Book 3) - Jennifer Nielsen - Bog

In order to go behind enemy lines, Frey has her face and body reconstructed for the ultimate disguise. Now she can move around freely in the city that once kept her captive -- and for the first time in her life, she is no longer her sister's physical twin. As they try to infiltrate their father's domain, the sacrifices may prove to be very high.