Fire Sea — Margaret Weis; Tracy Hickman

Abarrach, the Realm of Stone. Here, on a barren world of underground caverns built around a core of molten lava, the lesser races--humans, elves, and dwarves--seem to have all died off. Here, too, what may well be the last remnants of the once powerful Sartan still struggle to survive. For Haplo and Alfred--enemies by heritage, traveling companions by necessity--Abarrach may reveal more than either dares to discover about the history of Sartan... and the future of all their descendents.

Ages ago, sorcerers of unmatched power sundered a world into four realms--sky, fire, stone, and water--then vanished. Over time, magicians learned to work spells only in their own realms and forgot the others. Now only the few who have survived the Labyrinth and crossed the Death Gate know of the presence of all four realms--and even they have yet to unravel the mysteries of their severed world....