Most visitors to Skerry Island see only its lush greenery, picturesque cemetery, and quaint downtown. Yet generations of local women know that on Skerry, their benevolent witchcraft is at its most powerful.

Beatrice Barnard doesn't believe in magic. She definitely doesn't believe the predictions of the celebrity psychic who claims that she will experience seven miracles and soon after she will die. When she discovers her husband is cheating on her, Bea flees to Skerry Island, off the Pacific Northwest coast, in desperate need of solitude—taking her husband's birthday vacation by herself. Immediately upon arrival, she finds her life on the line as a rogue woodchopper blade almost kills her. Her survival feels like a miracle.

And then things get more miraculous when she discovers her twin sister, Cordelia, whom she never knew about, and her mother Astrid, who supposedly died when Beatrice was two years old. Astrid and Cordelia reveal that Beatrice (given name Beatrix) is an immensely powerful witch who can commune with the dead, like all the local Holland family witches. When their twin magic is joined, it shines like a beacon to the Velamen family, whose malevolent spirits are locked in an age-old struggle for magical dominance over the Hollands.

Beatrice doesn't know what to believe, but she begins to fear that the seven predicted miracles may occur, and that her imminent death will rip her away from her rediscovered family. Beatrice resolves to learn everything she can about her own power, in the hope of saving herself. But when her niece, Minna, goes missing, Bea's own life suddenly seems much less important. Beatrice must join her mother and her sister to save Minna even if she dies in the process.