The events of the novel take place in Europe and on an Atlantic island during an ice age nearly twenty thousand years ago. At first, Roy finds himself and his host Ram in a major trading post on the coast of Europe. Tall, fair stone-age people come to the post to pay homage to Ram, who has been on the continent for more than a year. The Athilantans have built an elaborate network of roads linking trading posts from the southern coast well into what would be Russia today. Roy finds more or less what he expected to find; the buildings are primitive structures with oil lamps and people are dressed in animal skins.

He is surprised when Ram boards the Athilantan ship that will take him home. The ship has electric lights and an unexpected form of propulsion—steam, Roy guesses. This level of technological sophistication...