“ North America,” said Pennyroyal, “is a Dead Continent. Everyone knows that. Discovered in the year 1924 by Christopher Columbo, the great explorer and detective, it became the homeland of an empire which once ruled the world, but which was utterly destroyed in the Sixty Minute War. It is a land of haunted red deserts, poison swamps, atomic-bomb craters, rust and lifeless rock. Only a few daring explorers venture there; archaeologists like Valentine and your young ladyfriend’s poor mother, out to salvage scraps of Old-Tech from the ancient bunker-complexes.

“And yet one hears rumours. Stories. Tales told by drunken old sky-dogs in run-down air-caravanserais. Yarns about airships that have been blown off course and found themselves flying over a very different sort of America: a green landscape of forests and grasslands and vast blue lakes. About fifty years ago a flyer named Snori Ulvaeusson was supposed to have actually landed in a green enclave he called Vineland, and made a map of it for the Lord Mayor of Reykjavik, but of course when modern researchers went looking for the map they found no trace of it in the Reykjavik library. As for the other accounts, the punchline is always the same: the airman spends years trying to find the place again, but never can. Or else he sets down his ship only to find that the greenery which looked so inviting from above is really only toxic algae blooming on a crater-lake.

“But true historians like ourselves, Tom, know that within such legends there often lurks a seed of truth. I gathered together all the stories I’d heard, and decided that there was something there worth following up. Is America really dead, as wise men like Valentine have always told us? Or could there be a place, far to the north of the dead cities which the Old-Tech hunters visit, where rivers of meltwater spilling from the edge of the Ice Wastes have washed away the poisons and made the Dead Continent begin to flower again?