From the New York Times bestselling author of The Drowning Kind comes a genre-defying new novel, inspired by Mary Shelley's masterpiece Frankenstein, that brilliantly explores the eerie mysteries of childhood and the evils perpetrated by the monsters among us.
1978: At her renowned treatment center in picturesque Vermont, the brilliant psychiatrist, Dr. Helen Hildreth, is acclaimed for her compassionate work with the mentally ill. But when she's home with her cherished grandchildren, Vi and Eric, she's just Gran—teaching them how to take care of their pets, preparing them home-cooked meals, providing them with care and attention and love.

Then one day Gran brings home a child to stay with the family. Iris—silent, hollow-eyed, skittish, and feral—does not behave like a normal girl.

Still, Violet is thrilled to have a new playmate. She and Eric invite Iris to join their Monster Club, where they catalogue all kinds of...