Galvin is a thrilling storyteller, untangling a dense plot in brief, suspenseful chapters, her prose almost trance-like: "The sand is softer, pristine, the colours too vivid I remember now, we were on a boat, a snorkelling trip. It was dawn." But Galvin allows every character time to unravel. She is particularly good on the relationship between the two orphaned sisters, marked by Aster's poignant efforts to assume their mother's role: "I never remind her to brush her hair and I always forget to check she's cleaned her teeth. I hear her suck her thumb again, and I close my eyes, swept with a desperate fear that something bad will happen to Poppy because I can't look after her properly."
This teen sci-fi thriller is breathtakingly daring and imaginative but has just enough grounding in reality to make it almost believable. Exploring themes of bereavement, survival, science and ecology, it will appeal to a wide readership and keep readers gripped to the very last page.