From bestselling author Abi Elphinstone comes a wondrous new series about four secret unmapped kingdoms hidden in our own world! Casper Tock hates risks and is allergic to adventures. So it comes as a nasty shock to him one day when he hides from bullies in an ancient grandfather clock—and ends up finding an entire world inside. Casper discovers that this sky kingdom of Rumblestar is one of the four Unmapped Kingdoms in charge of controlling the weather in Casper’s own world. What’s more, Casper is now stuck in Rumblestar, and the only person there who doesn’t think he’s a demon spy is a strange girl named Utterly, who hates rules and is allergic to behaving. All Casper wants is to find his way home, but Rumblestar is in trouble. An evil harpy called Morg is trying to steal the magic of the Unmapped Kingdoms. And if these kingdoms fall, Casper’s world will be destroyed as well. And so, together with Utterly and her miniature dragon, Arlo, Casper embarks on a quest full of cloud giants, storm ogres, and drizzle hags. Can he, Utterly, and Arlo—the unlikeliest of heroes—save both their worlds from the clutches of Morg? Abi Elphinstone grew up in Scotland where she spent most of her childhood running wild across the moors, hiding in tree houses and building dens in the woods. After being coaxed out of her tree house, she studied English at Bristol University and then worked as an English teacher in Tanzania, Berkshire and London. She is the bestselling author of the  Ember Spark  series , Sky Song, Saving Neverland,   The Unmapped Chronicles , The Dreamsnatcher trilogy and, for younger readers, The Snow Dragon  and The Frost Goblin . When she's not writing, Abi works as a trustee for The Lamp of Lothian, speaks in schools about the transformative power of reading and writing and travels the world looking for her next story. Her latest adventures include living with the Kazakh Eagle Hunters in Mongolia and dog-sledding across the Arctic.  Chapter 1 Chapter 1 Casper crouched inside the lost and found basket in the corridor outside his classroom. The school timetable stated, very firmly, that he should be in Mr. Barge’s geography lesson, but his own timetable, which was at this second folded neatly into his palm, stated that he should be exactly where he was—surrounded by dirty blazers and smelly sports uniforms. Casper shifted his weight. Thirty minutes was a long time to be wedged inside a wicker basket, but it had become an important part of his Thursday afternoons. Because only by telling Mr. Barge that he had a piano lesson or a dentist appointment or an errand to run for the headmaster, and hiding in the lost and found instead, could Casper overhear the lesson and the homework instructions (thereby not falling behind in his studies or causing Mr. Barge to question his absences) while avoiding crossing paths with Candida and Leopold. By and large, Little Wallops Boarding School was a friendly place—and with its wood-paneled dining room, enormous fireplaces, and stone gargoyles it was rather beautiful, too—but in every school there are rotten eggs, the sort of children who write complaint letters to Father Christmas and ask their parents for a pocket-money raise. Candida and Leopold were two such children, and while Casper had previously managed to avoid both of them because they were in different classes, this term Candida and Leopold’s geography teacher had been out sick, so Casper’s personal timetable had needed some considerable adjustments. Casper risked a peep over the top of the basket. Mr. Barge always left his classroom door open (apparently it made hurling pupils out of lessons far more straightforward), and though from where he crouched Casper couldn’t see Candida or Leopold, or any of his classmates for that matter, he had a clear view of his teacher, who was, at this moment, flinging exercise books toward his pupils. “Down the center, Ben—quick, catch! On the wing, Ruby—look sharp!” Mr. Barge, a middle-aged man the size and shape of a drawbridge, doubled up as a geography teacher and a rugby coach, and he often got the two confused. Another exercise book shot, like a rugby ball, across the room, and Mr. Barge’s voice boomed through the door and out into the corridor. “Coming through, Oliver! You’ll have to jump for this one!” A short, sharp thump followed. Casper winced. He guessed Oliver had tried to jump for his book—and missed. Mr. Barge performed several lunges, which made his suit squeak at the seams, then he threw his class a toothy grin. “Hustle in, Year Six. Hustle in.” There were a few nervous scrapes as the pupils pulled their chairs closer. “We’ve all seen the newspaper headlines these past few weeks: What the nation thought was a one-off hurricane in England at the beginning of March has now escalated into a worldwide weather crisis. The hurricanes across Europe are becoming more frequent—the United Kingdom has been ravaged by gale-force winds fo