The Girl in Wooden Armor

Soon after her thirteenth birthday, Hetty receives a mysterious letter from her grandmother asking, «Come as soon as possible». She has always been a bit strange, sending her granddaughter branches instead of gifts, wandering in the woods, and clearly keeping some kind of secret. And now she has completely disappeared. Arriving in the foggy village of Brookwood, Hetty discovers that her grandmother's house is empty, and something is amiss around. In her attempts to find her grandmother, Hetty ends up in an ancient castle and meets members of the Order of the Broken Tree. But who are they protecting the village from?