“Whimsical,humorousrichly built…A delightful series opener.” —Kirkus Reviews 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 moreCasper is now stuck in Rumblestarand the only person there who doesn’t think he’s a demon spy is a strange girl named Utterlywho hates rules and is allergic to behaving. All Casper wants is to find his way homebut Rumblestar is in trouble. An evil harpy called Morg is trying to steal the magic of the Unmapped Kingdoms. And if these kingdoms fallCasper’s world will be destroyed as well. And sotogether with Utterly and her miniature dragonArloCasper embarks on a quest full of cloud giantsstorm ogresand drizzle hags. Can heUtterlyand Arlo—the unlikeliest of heroes—save both their worlds from the clutches of Morg?