The only life Mae has ever known is on the island, living on the charity of the wealthy Prosper family who control the magic on the island and the spirits who inhabit it. Mae longs for magic of her own and to have a place among the Prosper family, where her best friend, Coco, will see her as an equal, and her crush, Miles, will finally see her. Now that she’s eighteen, Mae knows her time with the Prospers may soon come to an end. But tonight is First Night, when the Prospers and their high-society friends return to the island to celebrate the night Lord Prosper first harnessed the island’s magic and started producing aether – a magical fuel source that has revolutionized the world. With everyone returning to the island, Mae finally has the chance to go after what she’s always wanted. When the spirits start inexplicably dying, Mae starts to realize that things aren’t what they seem. And Ivo, the reclusive, mysterious heir to the Prosper magic, may hold all the answers – including a secret about Mae’s past that she doesn’t remember. As Mae and her friends begin to unravel the mysteries of the island, and the Prospers’ magic, Mae starts to question the truth of what her world was built on.