“We’d better get out of the open just the same,” Toller said, urging her towards the buildings on the north side of the gardens. People all about him were scanning the heavens, but — such was the power of conviction and habit — only a few were hurrying to take cover. The ptertha were an implacable natural enemy, but a balance had been struck long ago and the very existence of civilisation was predicated on the ptertha’s behaviour patterns remaining constant and foreseeable. It was quite unthinkable that the blindly malevolent globes could make a sudden radical change in their habits — in that respect Toller was at one with the people around him — but the news from the provinces had implanted the seeds of unease deep in his consciousness. If the ptertha could change in one way — why not in another?

A woman screamed some distance to Toller’s left, and the single inarticulate pulse of sound framed the real world’s answer to his abstract musings. He looked in the direction of the scream and saw a single ptertha descend from the sun’s cone of brilliance. The blue-and-purple globe sank into a crowded area at the centre of the gardens, and now men were screaming too, counterpointing the continuing blare of the alarm horns. Fera’s body went rigid with shock as she glimpsed the ptertha in the last second of its existence.

“Come on!” Toller gripped her hand and sprinted towards the peristyled guildhalls to the north. In his pounding progress across the open ground he had scant time in which to look out for other ptertha, but it was no longer necessary to search for the globes. They could be readily seen now, drifting among the rooftops and domes and chimneys in placid sunlight.

There could only have been a few citizens of the Kolcorronian empire who had never had a nightmare about being caught on exposed ground amid a swarm of ptertha, and in the next hour Toller not only experienced the nightmare to the full but went beyond it into new realms of dread. Displaying their terrifying new boldness, the ptertha were descending to street level all over the city — silent and shimmering — invading gardens and precincts, bounding slowly across public squares, lurking in archways and colonnades. They were being annihilated by the panic-stricken populace, and it was here that the terms of the ancient nightmare became inadequate for the actuality — because Toller knew, with a bleak and wordless certainty, that the invaders represented the new breed of ptertha.

They were the plague-carriers.

In the long-running debate about the nature of the ptertha, those who spoke in support of the idea that the globes possessed some qualities of mind had always pointed to the fact that they judiciously avoided cities and large towns. Even in sizable swarms the ptertha would have been swiftly destroyed on venturing into an urban environment, especially in conditions of good visibility. The argument had been that they were less concerned with self-preservation than with avoiding wasting their numbers in futile attacks — clear evidence of mentation — and the theory had had some validity when the ptertha’s killing range was limited to a few paces.

But, as Toller had intuited at once, the livid globes drifting down in Ro-Atabri were plague-carriers.

For every one of them destroyed, many citizens would be lost to the new kind of poisonous dust which killed at great range, and the horror did not stop there — because the grim new rules of conflict decreed that each direct victim of a ptertha encounter would, in the brief time remaining to them, contaminate and carry off to the grave perhaps dozens of others.

An hour elapsed before the wind conditions changed and brought the first attack on Ro-Atabri to an end, but — in a city where every man, woman and child was suddenly a potential mortal enemy and had to be treated as such — Toller’s nightmare was able to continue for much, much longer.… A rare band of rain had swept over the region during the night and now, in the first quiet minutes after sunrise, Toller Maraquine found himself looking down from Greenmount on an unfamiliar world. Patches and streamers of ground-hugging mist garlanded the vistas below, in places obscuring Ro-Atabri more effectively than the blanket of ptertha screens which had been thrown over the city since the first attack, almost two years earlier. The triangular outline of Mount Opelmer rose out of an aureate haze to the east, its upper slopes tinted by the reddish sun which had just climbed into view.

Toller had awakened early and, driven by the restlessness which recently had been troubling him more and more, had decided to get up and walk alone in the grounds of the Peel.

He began by pacing along the inner defensive screen and checking that the nets were securely in place. Until the onslaught of the plague only rural habitations had needed ptertha barriers, and in those days simple nets and trellises had been adequate — but all at once, in town and country alike, it had become necessary to erect more elaborate screens which created a thirty-yard buffer zone around protected areas. A single layer of netting still sufficed for the roofs of most enclosures, because the ptertha toxins were borne away horizontally in the wind, but it was vital that the perimeters should be double screens, widely separated and supported by strong scaffolding.

Lord Glo had gratified Toller by giving him, in addition to his normal duties, the responsible and sometimes dangerous task of overseeing the construction of the screens for the Peel and some other philosophy buildings. The feeling that he was at last doing something important and useful had made him less unruly, and the risks of working in the open had provided satisfactions of a different kind. Borreat Hargeth’s only significant contribution to the anti-ptertha armoury had been the development of an odd-looking L-shaped throwing stick which flew faster and farther than the standard Kolcorronian cruciform, and in which in the hands of a good man could destroy globes at more than forty yards. While supervising screen construction Toller had perfected his skill with the new weapon, and prided himself on having lost no workers directly to the ptertha.

That phase of his life had drawn to its ordained close, however, and now — in spite of all his efforts — he was burdened with a sense of having been caught like a fish in the very nets he had helped to construct. Considering that more than two thirds of the empire’s population had been swept away by the virulent new form of pterthacosis, he should have been counting himself fortunate to be alive and healthy, with food, shelter and a lusty woman to share his bed — but none of those considerations could offset the gnawing conviction that his life was going to waste. He instinctively rejected the Church’s teaching that he had an endless succession of incarnations ahead of him, alternating between Land and Overland; he had been granted only one life, one precious span of existence, and the prospect of squandering what remained of it was intolerable.

Despite the buoyant freshness of the morning air, Toller felt his chest begin to heave and his lungs to labour as though with suffocation. Close to sudden irrational panic, desperate for a physical outlet for his emotions, he reacted as he had not done since his time of exile on the Loongl peninsula. He opened a gate in the Peel’s inner screen, crossed the buffer zone and went through the outer screen to stand on the unprotected slope of Greenmount. A strip of pasture — deeded to the philosophy order long ago — stretched before him for several furlongs, its lower end slanting down into trees and mist. The air was almost completely still, so there was little chance of encountering a stray globe, but the symbolic act of defiance had an easing effect on the psychological pressure which had been building within him.

He unhooked a ptertha stick from his belt and was preparing to walk farther down the hill when his attention was caught by a movement at the bottom edge of the pasture. A lone rider was emerging from the swath of woodland which separated the philosophers’ demesne from the adjacent city district of Silarbri. Toller brought out his telescope, treasured possession, and with its aid determined that the rider was in the King’s service and that he bore on his chest the blue-and-white plume-and-sword symbol of a courier.