Andre Norton: The People of the Crater

Now that the latest world wide war has ended, Captain Garin, the hottest fighter pilot of the American force, is reduced to poverty and hunger as a civilian. He is approached to work for an expedition to Antarctica to investigate an odd mist that obscures everything. Eagerly accepting the job he finds himself 'summoned' by strange creatures in that mist to fight the Caves of Darkness. His mission is mysterious but exciting and apparently foretold. 'Send the Black Throne to dust; conquer the Black Ones, and bring the Daughter from the Caves of Darkness.' These were the tasks Garin must perform to fulfill the prophecy of the Ancient Ones—and establish his own destiny in this hidden land!'