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.