From the author of The Unspoken Name comes a riveting Gothic fantasy mystery full of uncanny magic, long-guarded secrets, and a deadly trial to inherit a legendary power.

“There is nobody alive who knows what really happened—except for me. I was there. I saw it all.”

The Mallory cousins have been summoned to their ancestral home by their great-aunt Sophia—or as the world knows her, the great Banisher, warden of the Isles and the singular defense against unspeakable otherworldly horrors.

Whoever can survive on the remote island for ten days and ten nights will inherit her house, her title, and her magic.

But the island is a labyrinth of deadly puzzles, terrifying ghosts, and scheming cousins with their own scores to settle. By the time the ten days are up, almost everyone on the island will be dead.

Almost everyone. Because someone else was there, witness to it all. And the story they tell is far darker than the blood coating the grounds of that cursed place.

“Effortlessly marries the complex clockwork investigations of writers like Yokomizo and Christie with dark, ghoul-haunted fantasy, and the result is a befouled chocolate box of delights.”—Tamsyn Muir, New York Times bestselling author of Gideon the Ninth

"Riveting, labyrinthine, and ruthlessly satisfying."—Olivie Blake, New York Times bestselling author of The Atlas Six

“One of the most perfectly constructed fantasy novels I’ve ever read.”—Shelley Parker-Chan, USA Today bestselling author of She Who Became the Sun