IMPOSSIBLE CAUSES

When newcomers move to an isolated island, old secrets threaten long-established order in this engrossing psychological thriller with hints of magic.

This is the first novel for adults by British YA author Mayhew (The Electrical Venus, 2018, etc.). Many of its characters, though, are teens; one of its dual protagonists is teenager Viola Kendrick. After a personal disaster, Viola’s mother hears a radio show about Lark, an isolated island in the North Sea. The tight-knit, religious community there is cut off from all outside contact each year from August to April. Viola and her mother, who’s suffering from depression, arrive just in time for the school year, as does another outsider, teacher Ben Hailey. The island’s only school hasn’t had a male teacher in living memory. Its only male staffer is the headmaster, Jacob Crane, who is the most powerful man on the island. But the handsome new science teacher soon charms everyone, particularly the book’s other protagonist, teacher Leah Cedars, who narrates her chapters in first person. Leah is a “pure catch,” as Lark natives are called, with distinctive ink-black hair; although she knows it will draw disapproval, she falls hard for Hailey. Viola is interested in their relationship, but she’s more obsessed with the Elder Girls, as the three senior girls in the school are called. Britta Sayers, Jade-Marie Ahearn, and Anna Duchamp are behaving strangely, and Mr. Hailey seems to be involved. The rumors are that the girls might be practicing old pagan ways, and Viola’s spying seems to confirm it, although what is driving them to rebel is a mystery. Then someone dies. Mayhew moves the plot around in time, beginning with the discovery of the dead body and then shifting back months to the outsiders’ arrival. Dates on each chapter help keep the complex structure moving smoothly.

Engaging characters, well-crafted suspense, and a tone of growing, claustrophobic dread add up to an effective thriller.