When a woman finds a rare illustrated book about the imaginary world she created for her missing sister, long-buried secrets from their childhood in wartime England resurface.

In 1939 London, fourteen-year-old Hazel and five-year-old Flora are sent to a village to escape the war. Living in a stone cottage by the River Thames, Hazel distracts Flora with walks and games, including a fairy tale about a magical land – their secret place. But tragedy strikes when Flora disappears near the riverbank. Blaming herself, adult Hazel carries the guilt and works in a London bookstore.

When a package arrives containing Whisperwood and the River of Stars – the imaginary world she created for Flora – Hazel wonders if her sister is alive after twenty years. As Hazel feverishly revisits her past relationships and wounds, her career and future hang in the balance. An astonishing twist ultimately reveals the truth in this transporting novel about sisterhood, conflicted love, and the power of storytelling.