It had become obvious to Toller Maraquine and some others watching on the ground that the airship was heading into danger, but — incredibly — its captain appeared not to notice.

“What does the fool think he’s doing?” Toller said, speaking aloud although there was nobody within earshot. He shaded his eyes from the sun to harden his perception of what was happening. The background was a familiar one to anybody who lived in those longitudes of Land — flawless indigo sea, a sky of pale blue feathered with white, and the misty vastness of the sister world, Overland, hanging motionless near the zenith, its disk crossed again and again by swathes of cloud. In spite of the foreday glare a number of stars were visible, including the nine brightest which made up the constellation of the Tree.

Against that backdrop the airship was drifting in on a light sea breeze, the commander conserving power crystals. The vessel was heading directly towards the shore, its blue-and-grey envelope foreshortened to a circle, a tiny visual echo of Overland. It was making steady progress, but what its captain had apparently failed to appreciate was that the onshore breeze in which he was travelling was very shallow, with a depth of not more than three-hundred feet. Above it and moving in the opposite direction was a westerly wind streaming down from the Haffanger Plateau.

Toller could trace the flow and counterflow of air with precision because the columns of vapour from the pikon reduction pans along the shore were drifting inland only a short distance before rising and being wafted back out to sea. Among those man-made bands of mist were ribbons of cloud from the roof of the plateau — therein lay the danger to the airship.

Toller took from his pocket the stubby telescope he had carried since childhood and used it to scan the cloud layers. As he had half expected, he was able within seconds to pick out several blurry specks of blue and magenta suspended in the matrix of white vapour. A casual observer might have failed to notice them at all, or have dismissed the vague motes as an optical effect, but Toller’s sense of alarm grew more intense. The fact that he had been able to spot some ptertha so quickly meant that the entire cloud must be heavily seeded with them, invisibly bearing hundreds of the creatures towards the airship.

“Use a sunwriter,” he bellowed with the full power of his lungs. “Tell the fool to veer off, or go up or down, or…”

Rendered incoherent by urgency, Toller looked all about him as he tried to decide on a course of action. The only people visible among the rectangular pans and fuel bins were semi-naked stokers and rakers. It appeared that all of the overseers and clerks were inside the wide-eaved buildings of the station proper, escaping the day’s increasing heat. The low structures were of traditional Kolcorronian design — orange and yellow brick laid in complex diamond patterns, dressed with red sand-stone at all corners and edges — and had something of the look of snakes drowsing in the intense sunlight. Toller could not even see any officials at the narrow vertical windows. Pressing a hand to his sword to hold it steady, he ran towards the supervisors’ building.

Toller was unusually tall and muscular for a member of one of the philosophy orders, and workers tending the pikon pans hastily moved aside to avoid impeding his progress. Just as he was reaching the single-storey building a junior recorder, Comdac Gurra, emerged from it carrying a sunwriter. On seeing Toller bearing down on him, Gurra flinched and made as if to hand the instrument over. Toller waved it away.

“You do it,” he said impatiently, covering up the fact that he would have been too slow at stringing the words of a message together. “You’ve got the thing in your hands — what are you waiting for?”

“I’m sorry, Toller.” Gurra aimed the sunwriter at the approaching airship and the glass slats inside it clacked as he began to operate the trigger.

Toller hopped from one foot to the other as he watched for some evidence that the pilot was receiving and heeding the beamed warning. The ship drifted onwards, blind and serene. Toller raised his telescope and concentrated his gaze on the blue-painted gondola, noting with some surprise that it bore the plume-and-sword symbol which proclaimed the vessel to be a royal messenger. What possible reason could the King have for communicating with one of the Lord Philosopher’s most remote experimental stations?

After what seemed an age, his enhanced vision enabled him to discern hurried movements behind the ship’s foredeck rails. A few seconds later there were puffs of grey smoke along.the gondola’s left side, indicating that its lateral drive tubes were being fired. The airship’s envelope rippled and the whole assemblage tilted as the craft slewed to the right. It was rapidly shedding height during the manoeuvre, but by then it was actually grazing the cloud, being lost to view now and again as it was engulfed by vaporous tendrils. A wail of terror, fine-drawn by distance and flowing air, reached the hushed watchers along the shore, causing some of the men to shift uneasily.

Toller guessed that somebody on board the airship had encountered a ptertha and he felt a thrill of dread. It was a fate which had overtaken him many times in bad dreams. The essence of the nightmare was not in visions of dying, but in the sense of utter hopelessness, the futility of trying to resist once a ptertha had come within its killing radius. Faced by assassins or ferocious animals, a man could — no matter how overwhelming the odds — go down fighting and in that way aspire to a strange reconciliation with death, but when the livid globes came questing and quivering, there was nothing that could be done.

“What’s going on here?” The speaker was Vorndal Sisstt, chief of the station, who had appeared in the main entrance of the supervisors’ building. He was middle-aged, with a round balding head and the severely upright posture of a man who was self conscious about being below average in height. His neat sun-tanned features bore an expression of mingled annoyance and apprehension.

Toller pointed at the descending airship. “Some idiot has travelled all this distance to commit suicide.”

“Have we sent a warning?”

“Yes, but I think it was too late,” Toller said. “There were ptertha all round the ship a minute ago.”

“This is terrible,” Sisstt quavered, pressing the back of a hand to his forehead. “I’ll give word for the screens to be hoisted.”

“There’s no need — the cloud base isn’t getting any lower and the globes won’t come at us across open ground in broad daylight.”

“I’m not going to take the risk. Who knows what the…?” Sisstt broke off and glared up at Toller, grateful for a safe outlet for his emotions. “Exactly when did you become empowered to make executive decisions here? In what I believe to be my station? Has Lord Glo elevated you without informing me?”

“Nobody needs elevation where you’re concerned,” Toller said, reacting badly to the chiefs sarcasm, his gaze fixed on the airship which was now dipping towards the shore.

Sisstt’s jaw sagged and his eyes narrowed as he tried to decide whether the comment had referred to his physical stature or abilities. “That was insolence,” he accused. “Insolence and insubordination, and I’m going to see that certain people get to hear about it.”

“Don’t bleat,” Toller said, turning away.

He ran down the shallow slope of the beach to where a group of workers had gathered to assist in the landing. The ship’s multiple anchors trailed through the surf and up on to the sand, raking dark lines in the white surface. Men grabbed at the ropes and added their weight to counter the craft’s skittish attempts to rise on vagrant breezes. Toller could see the captain leaning over the forward rail of the gondola, directing operations. There appeared to be some kind of commotion going on amidships, with several crewmen struggling among themselves. It was possible that somebody who had been unlucky enough to get too close to a ptertha had gone berserk, as occasionally happened, and was being forcibly subdued by his shipmates.