The fight for the hidden realm by Siobhan McDermott

In a village above the cloud sea, twelve-year-old orphan Zhi Ging is chosen to become a Silhouette, an apprentice to the immortals. Taken to an underwater realm, she begins her training, competes in thrilling challenges and discovers she can awaken a special sort of dragon. But Silhouettes who fail the challenges seem to be disappearing and rumours are spreading of a growing dark force that threatens her world. Zhi Ging begins to realise that there is so much she has yet to learn about the world of the immortals – and herself.