On the strange, stormy island of Blightsend, 12-year-old Delphernia Undersea has spent her whole life in the cloister of turnaway girls, hidden from sea and sky by a dome of stone and the laws of the island. Outside, the Masters play their music. Inside, the turnaway girls silently make that music into gold. Making shimmer, Mother Nine calls it. But Delphernia can’t make shimmer. She would rather sing than stay silent. When a Master who doesn’t act like a Master comes to the skydoor, it’s a chance for Delphernia to leave the cloister. Outside the stone dome, the sea breathes like a wild beast, the sky watches with stars like eyes, and even the gardens have claws. Outside, secrets fall silent in halls without sound. And outside, Delphernia is caught between the island’s sinister Custodian and its mysterious Childer-Queen.