Tuesdays at the Castle by Jessica Day George

Bloomsbury, 2013. ISBN 9781408831984.
For or a different take on the Princess theme, what can beat a feisty and determined young Princess trying to save her family and kingdom with the help of an unpredictable Castle.
Tuesday at Castle Glower is like no other day of the week. If the Castle is bored, that is the day it grows new rooms or towers or even whole wings, fully furnished!
The Castle has an influence on the kingdom greater than most royal advisers. Growing corridors, sealing rooms, or suddenly growing door or staircases the human inhabitants are manipulated and through the quality of the furnishing in the rooms used by visitors and inhabitants, it has informed royal decisions for generations.
Princess Celie the youngest child of King Glower the Seventy Ninth loves the Castle and it seems to love her back. When her parents and oldest brother Bran are reported ambushed and murdered on their way home from Wizard School Graduation, Celie and her older siblings Lilah and Rolf are bereft.
Rolf as crown prince, chosen by the Castle of course, is considered too young by the Council so they appoint themselves and Prince Khelsh of the neighbouring Kingdom of Vhervhine as regents to advise Rolf.
The children believe that their parents are still alive, because the Castle hasn't altered their rooms, and set out to discover the truth. With the Castle's help they discover Prince Khelsh and the Emissary to Foreign Lands plotting to take over the kingdom. Determined to save the Castle and themselves, the children and various supporters, from the staff to a visiting Prince, embark on a series of delaying and mischievous tactics, aided and abetted by the Castle itself.
Celie is a strong and engaging character; however it is the Castle which is the most interesting and influential character in the story.
Sue Keane