The day Oona was kicked out of her mother's coven at eighteen, she gave up on her dreams of harnessing the witchcraft she'd imagined was her birthright. Years later, she's carved out an ordinary life with her husband, though she is filled with a longing she can barely name. If she can only carry a pregnancy to term, become a mother, then - according to island lore - she will come into her magic. But after multiple pregnancies end in miscarriages, Oona begins to feel desperate. Without the money to seek medical treatment, she decides she must return to the rugged, windswept island where she was raised - and to her dark, enigmatic mother whose coven claims to be able to harness witchcraft to help women struggling to conceive. Due to her acrimonious departure, Oona will have to return under the cover of anonymity. But there are dark forces at work on the island, and as her time there grows more harrowing, the truth threatens to come to light. How far will Oona go to access the power she knows her mother still commands?