The Charmed Children of Rookskill Castle by Janet Fox

At one point in this middle-grade novel one of the characters remarks on how it’s weird to be living in a “crazy maybe haunted, maybe spy-filled castle in Scotland,” and yeah, this book is quite the mix of things. It’s 1940 and Kat Bateson and her two siblings are sent to a castle somewhere north of Edinburgh so they won’t be in London in the midst of the Blitz: a relative of her great-aunt’s has a wife who’s started a school in their castle, for evacuee children. But it’s clear to Kat from the start that something is “off” about Lady Eleanor and the rest of the castle’s inhabitants. And it’s not particularly reassuring to be told things upon arrival like “The Lady insists we lock you in at night” and “If you hear any odd noises, it’s nothing. Castles as old as this are filled with odd noises.” The reader, meanwhile, is given the whole backstory, from 1746 onwards, which involves a magical chatelaine and the stealing of children’s souls. Meanwhile, the kids find “a secret hiding place” with “something—or someone—locked inside that makes terrible shrieky noises”: a prisoner? a ghost? or something more rational but maybe more dangerous … like the short-wave radio of a Nazi spy? I like how Kat, who likes to spend “time with facts and figures and puzzles” (and who’s initially convinced there’s a rational explanation for everything) ultimately finds herself having not only to believe in magic, but to use it. I probably would have been freaked out by this book as a kid—I found it pretty creepy even as an adult, while also finding the plot totally engrossing.