Author: Scott Westerfeld FREY AND RAFI ARE INSEPARABLE... TWO EDGES OF THE SAME KNIFE. BUT FREY'S VERY EXISTENCE IS A SECRET. Frey is Rafi's twin sister - and her body double. While Rafi was raised to be the perfect daughter, Frey has been taught to kill. Her only purpose is to protect her sister - to sacrifice if she must. When her father sends Frey in Rafi's place as collateral in a precarious deal, she becomes the perfect impostor. But Col, the son of a rival leader, is getting close enough to spot the killer inside her. Can Frey trust him with the truth and risk becoming her own person?