It was the sixth, and by far the worst, storm—-one of the mysterious climactic outbursts that materialized from a clear sky over half a dozen of the Earth’s great cities, did appalling damage, and then disappeared, “as if a switch had been turned off”, as one observer put it. Now one of these onslaughts had struck at London, and had caused one of the great passenger-carrying spaceships of the Dodd Line to crash as she came in to land. One of the survivors, however, had seen something before the ship went out of control—a strange aurora over the South Pole. Called in for consultation, after an investigating jet bomber had vanished in frozen wastes of Antarctica, the Golden Amazon herself set off for the South Pole in the “Ultra”—-to come up against one of the hardest assignments in her adventurous life, with nothing less than the collapse of world civilization as the penalty if she failed.