In his continuing adventures, Twig, now sixteen years old, joins the crew of his father's sky pirate ship and embarks on a dangerous mission to collect the powerful stromphrax, a substance that purifies water and also prevents the city of Sanctaphrax from floating away.

Apprenticed to the Most High Academe of Sanctaphrax, a floating city of scholars, gossip, and treachery, fourteen-year-old Quint runs increasingly dangerous errands, which eventually bring him to a place of gruesome monsters that threaten his life and those of his friends.

Rook Barkwater, the young librarian knight, attempts to stop Vox Verlix, the Most High Academe, in his plot to take over Edgeworld once again.

Quint finally begins his training at the Knights Academy, Maris adjusts to life in Undertown, and Sanctaphrax shivers in anticipation of a legendary storm, while a storm of a different kind brews between sky-scholars and earth-scholars.

Nate Quarter is a lowly lamplighter in the phraxmines of the Eastern Woods, until treachery forces him to flee for his life to the mighty city of Great Glade.
But these are turbulent times. In far-off Hive, the spectacular city founded by the goblin tribes, the clan leaders are preparing for war. And out beyond the dread Nightwoods, in the fabled gardens of Riverrise, a one-eyed waif jealously guards the life-giving waters of the mystical Riverrise...