I think it's best that you go into this book knowing as little as possible. All I had to go by was the few lines on the back of the book, and I'm so glad I didn't know anymore than that. It makes the story even more exciting and magical as you discover things along with the characters.

This is a dual narrative between Aster and Sam. Aster is a great character, she seems much older than she is, but her age is only mentioned once and it's only reflecting on the book that I realised this. She is fiercely protective of her younger sister, and wonderfully independent. I loved her journey throughout the book as she shows her independence, and her willingness to accept the things that she experiences and sees. Sam's perspective was an unexpected one for me, but it really helped add context to the rest of the book, as Sam researches what has happened and helps fill in gaps in Aster's knowledge. Having Sam really enriches the story in a natural way.

Galvin has created a beautiful setting in the islands. They're rich, and diverse settings that prevent the setting from becoming monotonous. At the same time they're simple, and Galvin allows the reader to supplement her descriptions with their own imagination and idea of a tropical island, and surrounding seas. This stops any long and unnecessary descriptions and keeps the pace of the book moving.

I flew through this book as I wanted to know what was going on. I hadn't guessed correctly and I was pleasantly surprised by the direction the story takes, it was refreshing and new to me. I urge you to go into this book knowing as little as possible, it's really worth it.