A dark, gothic adventure set on the island of Anglesey in North Wales and featuring a very fantastical beast …

Wren lives in an ancient castle in the mountains near the sea. The wind whistles through it and the walls sing to her. Wren is busy inventing things, and her father is busy disapproving.

But the castle contains a mystery and as Wren is drawn further into it, she realises the answer lies in the very foundations of her home, foundations that are being shaken to their core…