Quinn Maybrook and her father have moved to tiny, boring Kettle Springs, to find a fresh start. But what they don’t know is that ever since the Baypen Corn Syrup Factory shut down, Kettle Springs has cracked in half. On one side are the adults, who are desperate to make Kettle Springs great again, and on the other are the kids, who want to have fun, make prank videos, and get out of Kettle Springs as quick as they can.

When Ann Stilwell arrives in New York City, she expects to spend her summer working as a curatorial associate at the Metropolitan Museum of Art. Instead, she finds herself assigned to The Cloisters, a gothic museum and garden renowned for its medieval art collection and its group of enigmatic researchers studying the history of divination. Desperate to escape her painful past, Ann is happy to indulge the researchers’ more outlandish theories about the history of fortune telling.

Simi prayed to the gods, once. Now she serves them as Mami Wata—a mermaid—collecting the souls of those who die at sea and blessing their journeys back home. But when a living boy is thrown overboard, Simi goes against an ancient decree and does the unthinkable—she saves his life. And punishment awaits those who dare to defy the gods.

Nineteen-year-old Signa Farrow, orphaned as a baby, has been raised by a string of guardians, each more interested in her wealth than her well-being—and each has met an untimely end. Her last remaining relatives are the Hawthornes, an eccentric family living at the glittering and gloomy estate of Thorn Grove. Thorn Grove’s patriarch, Elijah, mourns his late wife, Lillian, through wild parties and drink, while eldest son Percy grapples for control of the family’s waning reputation and daughter Blythe suffers from the same mysterious illness that killed her mother.

Annaleigh lives a sheltered life at Highmoor with her sisters and their father and stepmother. Once there were 12, but loneliness fills the grand halls now that four of the girls' lives have been cut short. Disturbed by a series of ghostly visions, Annaleigh becomes increasingly suspicious that her sister's deaths were no accidents. The girls have been sneaking out every night to attend glittering balls, dancing until dawn in silk gowns and shimmering slippers, and Annaleigh isn't sure whether to try to stop them or to join their forbidden trysts.