Celie is an eleven-year-old princess, the youngest of the four royal children of the kingdom of Sleyne. She lives in Castle Glower, a magical palace that seems to have a mind of its own because it changes its floorplan whenever it feels like doing so.

Celie shares a special emotional connection with the castle and is able to communicate with it in some unknown way. She’s also the only person who has memorized its intricate floorplan and compiled a 300-page atlas of its various rooms. Celie treats the castle like a friend and would give her life to defend it from those who wish it harm. In the end, she saves the castle and her royal family from invaders and is saved by the castle in turn when her own life is at risk.

• King Glower the Seventy-ninth is Celie’s father. He respects the wisdom of the castle and is a good and just king.

• Queen Celina is Celie’s mother. She was the beautiful daughter of the Royal Wizard when Glower married her. She is dedicated to the welfare of her family and the kingdom.

• Prince Bran is Celie’s eldest brother. Even though he is the eldest, the castle decided he would make a better wizard than a monarch, so he was sent to study at the College of Wizardry.