Kelanni - a planet tidally locked around a brown dwarf star. Ail-Kar - a white hole, a portal from another universe, rains meteoroids on to the surface of the planet Kelanni. But the so-called "lodestones" behave according to different physical laws, changing Kelanni`s society, its religion and its people. Now the land is ruled over by a mysterious Prophet. With the aid of the fearsome Keltar in their flying cloaks, he is forcing the Kelanni to mine lodestones, in order to build a machine whose terrible power can only be guessed at. Shann, an orphan, witnesses a battle between a Keltar and a stranger bearing a similar flying cloak. She sets out to track down the stranger, and is propelled into an extraordinary land of floating stones, strange communication devices and bizarre creatures.
Shann finds Lyall, a Kelanni driven by a past he will not discuss, to seek freedom for those suffering under the Prophet's heel. She learns of the technology behind the Keltars' power, and joins him on a mission to free the slaves and cut off the Prophet's supply of lodestones.
Meanwhile, Keris, a Keltar with impressive skills, is sent on a mission to track down the rebels. She is attacked by a flying creature and saved by the enigmatic Chandara. At their Great Tree, she receives a message transmitted by a woman from the past, who reveals the terrifying truth that the Prophet is out to destroy the Kelanni. Accompanied by Boxx, a Chandara who seems to speak only in riddles, Keris must travel to the other side of her world in order to retrieve a device that will enable her to disable the Prophets machine. She races to save the rebels from a trap set for them, joining the party
Together, they seek to cross the Great Barrier of Storms to the far side of the planet Kelanni, where none have ventured before. On their journey, they will traverse desert, prairie, high mountains and deep fire pits. They will come upon wondrous and terrifying beasts, meet peculiar characters and encounter advanced technology, left behind by a civilization from long ago. Ultimately they will face the Great Barrier itself and the unknown world that lies beyond, where they will find the answers each of them seeks. The key to both salvation and destruction that lies within the ultimate power of... "Lodestone".