Can you hear Atlantia breathing? For as long as she can remember, Rio has dreamed of the sand and sky Above—of life beyond her underwater city of Atlantia. But in a single moment, all Rio’s hopes for the future are shattered when her twin sister, Bay, makes an unexpected choice, stranding Rio Below. Alone, ripped away from the last person who knew Rio’s true self—and the powerful siren voice she has long silenced—she has nothing left to lose. Guided by a dangerous and unlikely mentor, Rio formulates a plan that leads to increasingly treacherous questions about her mother’s death, her own destiny, and the corrupted system constructed to govern the Divide between land and sea. Her life and her city depend on Rio to listen to the voices of the past and to speak long-hidden truths.