Eleven-year-old Maggie lives in Fennis Wick, enclosed and protected from the outside world by a boundary, beyond which the Quiet War rages and the dirty, dangerous wanderers roam. Her brother Jed is an eldest, revered and special. A hero. Her younger brother is Trig - everyone loves Trig. But Maggie's just a middler; invisible and left behind. Then, one hot September day, she meets Una, a hungry wanderer girl in need of help, and everything Maggie has ever known gets turned on its head.