In a dangerous future world where gigantic, traction-powered cities attack and devour each other, London hunts where no other predator dares. Hidden in its vast superstructure is a murderous creature that severs the right hands of its victims. A rebellious young aviatrix and a secretive scavenger boy are about to come face to face with a robotic Stalker that is terrifyingly out of control. This double book for older readers is published for World Book Day 2011, and is available free in exchange for a Ù1.00 WBD voucher, given to every UK school child.