When her mentor, Franklin Craft, goes inexplicably missing, gargoyle cadet Tiffany Noboru and her best friend Hedika put their ghost hunting skills to the test in a harrowing journey across the world of gargoyles. To find him, they must brave what lies beyond the protection of their walls, but avoiding ghosts out on the Endless See is only the beginning. Strange and dangerous creatures roam the blighted landscape between the Hollow Mountain and their uncharted destination, the gargoyle sanctuary Freefall, whose dying populace guards a terrible secret about her own world that some are willing to do anything to protect.