Castles traded places sometimes. Everyone knew that. It was always something that might happen, except that it never had in that valley, and nobody had really expected that it would. It was one of those unlikelihoods, like finding treasure, or being eaten by a wolf, or having a handsome, powerful stranger turn up to right all your wrongs. It could happen, except it didn't. Until all of a sudden it did. Traitors' Nest is the brand new YA fantasy novel by Frances Hardinge, in which castles in the Kingdom of Thaletal are moved around like chess pieces by enigmatic Players. The story follows 16-year-old Burr, whose village is disrupted by a new castle and Lord. What starts as a small rebellion escalates when the castle is moved, and Burr learns about a mysterious ancient maiden who uses magpies to collect her debts.