Daylight and flat terrain were conditions which did not favour the ptertha. They had virtually no self-propulsive capability in the horizontal plane, depending on air currents to carry them across the face of the land, which meant that an active man had little to fear from ptertha while he was crossing open ground. Assuming they had not blanketed the area — something which rarely happened in daytime — all he had to do was observe the globes closely and be aware of the wind direction. When menaced by a ptertha, it was simply a matter of waiting until just before it came within the killing radius, then running crosswind for a short distance and allowing the globe to drift helplessly by.

Lain stumbled to a halt in a gully, his mouth filling with the salt froth of exhaustion, and leaned on a rock to recover his breath. It was vital that he should still have reserves of strength and be nimble on his feet when he reached the plain. As the tumult in his chest gradually subsided he indulged himself in a visualisation of his next encounter with Leddravohr, and — incredibly — he felt his gaping mouth trying to form a grin. This was the irony of ironies! While the renowned military prince had fled to seek refuge from the ptertha, the mild-mannered philosopher had strolled back to the city, in need of no armour but his intellect. This was proof indeed that he was no coward, proof for all to see, proof that even his wife would have to.…

I’ve gone mad! The thought caused Lain to moan aloud in sheer self-loathing. I have truly lost what used to be my mind!

I permitted a savage to breach my defences with all his crossness and malice, his celebration of stupidity and glorification of ignorance. I let him debase me until I was prepared to throw away life itself in a weltering of hatred and pride — what laudable emotions! — and now I’m indulging in fantasies of childish revenge, so gratified by my own superiority that I haven’t even taken the basic precaution of making sure there are no ptertha at hand!

Lain straightened up and — sick with premonition — turned to look back along the gully.

The ptertha was barely ten paces away, well within its killing radius, and the breeze coursing along the gully was sweeping it closer to him with mind-freezing swiftness.

It swelled to encompass his view, its glistening transparencies tinged with purple and black. In one part of his mind Lain felt a perverse flicker of gratitude that the issue had been decided for him, so quickly and so finally. There was no point in trying to run, no point in trying to fight. He saw the ptertha as he had never seen one before, saw the livid swirlings of the toxic dust inside it. Was there a hint of structure there? A globe within a globe? Was a malign proto-intelligence knowingly sacrificing itself in order to destroy him?

The ptertha filled Lain’s universe.

It was everywhere — and then it was nowhere.

He took a deep breath and looked about him with the ruefully placid gaze of the man who has only one further decision to make.

Not here, he thought. Not in this blind and circumscribed place — it isn ’t at all suitable.

Recalling the higher slope which had afforded the good view to the east, he retraced his steps along the bed of the ancient stream, walking slowly now and emitting occasional sighs. When he reached the slope he sat on the ground with his back to an agreeably shaped boulder and arranged his robe in neat folds around his outstretched legs.

The world of his last day was laid out before him. The triangular outline of Mount Opelmer floated low in the sky, seemingly detached from the horizontal ribbons and speckled bands which represented Ro-Atabri and the derelict suburbs on the shores of Arle Bay. Closer and lower was the artificial community of the Skyship Quarter, its dozens of balloon enclosures an illusory city of rectangular towers. The Tree glittered in the southern heavens, its nine stars challenging the sun’s brilliance, and at the zenith a broad crescent of mellow light was spreading insensibly across the disk of Overland.

The whole span of my life and work is in that scene, Lain mused. I have brought my writing materials and should try to make some kind of a summation… not that the last thoughts of one who precipitated his own demise in such a ludicrous fashion would be of much interest or value to others… at most I could record what is already kno wn — that pterthacosis is not a bad death… as deaths go, that is… nature can be merciful…as the most horrific shark bites are often unaccompanied by pain, so the inhalation of ptertha dust can sometimes engender a strange mood of resignation, a chemical fatalism… in that respect at least, I appear to be fortunate… except that I am deprived of feelings which are mine by ancient right…

A burning sensation manifested itself below Lain’s chest and spread radial tendrils into the rest of his torso. At the same time the air about him seemed to grow cold, as though the sun had lost its heat. He put a hand into a pocket of his robe, brought out a bag made of yellow linen and spread it on his lap. There was a final duty to be performed — but not yet.

I wish Gesalla were here…Gesalla and Toller… so that I could give them to each other, or ask them to accept each other… irony piles upon irony… Toller always wanted to be different, to be more like me… and when he became the new Toller, I was forced to become the old Toller… to the final extent of throwing down my life for the sake of honour, a gesture which should have been made before my beautiful solewife was ravaged and defiled by Leddravohr… Toller was right about that, and I — in my so-called wisdom — told him he was wrong… Gesalla knew in her head that he was wrong, and in her heart that he was right…

A stab of pain in Lain’s chest was accompanied by a bout of shivering. The view before him was curiously flat. He could see more ptertha now. They were drifting down towards the plain in groups of two and three, but they had no relevance to what was left of his life. The dream-flow of his fragmentary thoughts was the new reality.

Poor Toller… he became what he aspired to be, and how did I reward him?…with resentment and envy…I hurt him on the day ofGlo’s interment, only able to do so because he loves me, but he responded to my childish spite with dignity and forbearance… brakka and ptertha go together…I love my “little brother#148; and I wonder if Gesalla even yet realises that she too… these things can take such a long time…of course brakka and ptertha go together — it’s a symbiotic partnership… only now do I understand why it was not in my heart to fly to Overland…the future is there, and the future belongs to Gesalla and Toller…could that be the underlying reason for my refusing to ride with Leddravohr, for choosing my own Bright Road?… was I making Toller’s way clear?… was I excising an unbalancing factor from the equation?…equations used to mean so much to me…

The fire in Lain’s chest was becoming hotter, expanding, causing him to struggle for breath. He was sweating profusely and yet his skin felt deathly cold, and the world was merely a scene painted on rippling cloth. It was time for the yellow hood.

Lain lifted it with clumsy fingers and drew it over his head — a warning to anyone who might come by that he had died of pterthacosis and that the body was not to be approached for at least five days. The eye slits were not in the right place, but he allowed his hands to fall to his side without adjusting them, content to remain in a private universe of formless and featureless yellow.

Time and space ran together in that undemanding microcosm.

Yes, I was right about the cave painting…the circle represents a ptertha… a colourless ptertha… one which has not yet developed its specialised toxins…who was it who once asked me if the ptertha used to be pink?… and what was my reply?… did I say the naked child is not afraid of the globe because he knows it will not harm him?…I know I have always disappointed Toller in one respect, by my lack of physical courage… my disregard for honour… but now he can be proud of me… I wish I could be there to see his face when he hears that I preferred to die rather than to ride with… isn’t it strange that the answer to the riddle of the ptertha has always been visible in the sky?… the Tree and the circle of Overland, symbolising the ptertha, co-existing in harmony… the brakka pollination discharges feed the ptertha with… with what?…pollen, green and purple, miglign?…and in return the ptertha seek out and destroy the brakka’s enemies… Toller should be protected from Prince Leddravohr… he believes himself to be equal to him, but I fear… I FEAR I HAVE NOT TOLD ANYONE ABOUT THE BRAKKA AND THE PTERTHA!… how long have I known?… is this a dream?… where is my lovely Gesalla?… can I still move my hands?… can I still…