Traitors Nest - Frances Hardinge

Castles traded places sometimes. Everyone knew that. It was always something that might happen, except that it never had. Until all of a sudden it did. Far above the valleys and villages of the Kingdom of Thaletal, a Great Game is played. Players move castles around the realm like chess pieces - and the ordinary villagers are mere pawns at the whim of their tactics. When 15-year-old Burr's peaceful village is disrupted by the arrival of an ominous new castle, he decides he's had enough. But what starts as a plucky coup soon escalates - and soon the castle is wrenched away to a far-flung corner of the kingdom, where whispers mount of a mysterious ancient maiden whose magpies collect her debts at dangerous prices. Here, the stakes are higher than the tallest turrets, and every move counts. Burr must work with his sisters and friends - and rely on the unexpected help of a strange and intriguing heiress - to unravel the secrets of the Magpie Maiden and the origins of the Great Game before he becomes just another casualty of the Players' deadly contest.