Stormy is an orphan and a kitchen skivvy. He tends the compost, he scrubs the floors, and watches feasts make their way up the mountain as he survives on bread and water. A skivvy is all that Stormy can hope to be. But Stormy has a secret. He wants to be a sky-rider, to soar amongst the clouds on spitfyres: flying horses that spit fire and smoke, and answer only to their riders. A chance meeting with an escaped convict turns Stormy’s life upside down. Sent up to the Academy he uncovers a web of lies, deceits and neglect, at the centre of which lies the mysterious thirteenth horse. Can Stormy save Thirteen, defeat the dark forces at work within the Academy and prove himself worthy as a sky-rider?