Random House Children’s Books has announced the North American publication of Impossible Creatures, the first in a middle-grade fantasy series from author Katherine Rundell. The book debuted in September 2023 to great fanfare in the U.K., where it was a Sunday Times bestseller, a Children’s Book of the Week in the Times, the Independent, and the Daily Telegraph, and the winner of the Waterstones Book of the Year award. Impossible Creatures is due September 10 from Alfred A. Knopf Books for Young Readers, with a first printing of 250,000 copies.

Nancy Siscoe, senior executive editor at Knopf, won North American rights in a multi-house, multi-round auction. Pete Knapp at Park & Fine Literary and Media brokered the deal on behalf of Claire Wilson at RCW Literary Agency.

Known for her globetrotting middle-grade adventures, including Rooftoppers, The Wolf Wilder, The Explorer, and The Good Thieves, Rundell creates a world of her own in her new fantasy. Impossible Creatures follows a boy named Christopher who discovers that he’s a descendant of a family of guardians of the Archipelago, a secret island chain where mythical creatures dwell—and are now in danger of extinction.

Rundell said in a statement, “As a kid, I longed to fly on the backs of dragons, and feed unicorns, and have my fingers gently chewed by a baby griffin, so Impossible Creatures was one of the most joyful experiences of my writing life. I wanted to try to make the creatures that populate the book as real and solid as possible, so that they would get under the skin of children, and teach them, too, to dream of impossible and not-quite-impossible things.”

Siscoe said of the acquisition, “I knew from the very first lines of the manuscript that this writer and this book were something special. Rundell introduces readers to the last magical place on earth: a world that is awesome, and beastly, and dangerous, and worthy of our fierce love and protection. She’s working in the grand tradition of children’s fantasy—it’s no surprise to me that reviewers are comparing her to Philip Pullman and C.S. Lewis and J.R.R. Tolkien—but her voice and her vision are also fresh and modern and invigorating.”

The North American edition will feature extensive interior artwork by Ashley Mackenzie, including a map and an illustrated bestiary. The first printing will also include a foil and embossed jacket, full-color endpapers, red stained edges, and a red case cover with gold stamping.

Impossible Creatures by Katherine Rundell, illus. by Ashley Mackenzie. Knopf, $19.99 September 10 ISBN 978-0-593-80986-0