A dragon’s brassy scream, the klaxon of Thread attack, stopped F’nor mid-sentence. The brown rider had swung toward his dragon, instinctively reacting to the alert, when F’lar caught him by the arm.

“You can’t fight thread with an unhealed wound, man. Where do they keep firestone here?”

Whatever criticism F’lar might have had of T’bor’s permissiveness at Southern, he could not fault the instant response of the Weyr’s fighting complement. Dragons swarmed in the skies before the alert had faded. Dragons swooped to weyrs while riders fetched fighting gear and firestone. The Weyr’s women and children were at the supply shed, stuffing sacks. A message had been sent to the seahold where fishermen from Tillek and Ista had established a settlement. They acted as ground crew. By the time F’lar was equipped and aloft, T’bor was issuing the coordinates.

Thread was falling in the west, at the edge of the desert where the terrain was swampy, where sharp broad-edged grasses were interspersed with dwarfed spongewoods and low berry bushes. For Thread, the muddy swamp was superb burrowing ground, with sufficient organisms on which to feed as the burrow proliferated and spread.

The wings, fully manned and in good order, went between at T’bor’s command. And, in a breath, the dragons hung again in sultry air and began to flame at the thick patches of Thread.

T’bor had signaled a low altitude entry, of which F’lar approved. But the wing movement was upward, seeking Thread at ever higher levels as they eliminated the immediate airborne danger. Weyrfolk and convalescents swelled the seahold group as ground crew but F’lar thought they’d need low ground support here. There were only three fighting queens, and where was Kylara?

F’lar directed Mnementh to fly a skim pattern just as the ground crews arrived, piling off the transport dragons, and flaming any patch of grass that seemed to move. They kept shouting to know where the leading Edge of the Fall was and F’lar directed Mnementh east by north. Mnementh complied, and abruptly turned due north, his head barely skimming the vegetation. He backwinged so abruptly that he nearly offset his rider. He hovered, peering so intently at the ground, that F’lar leaned over the great neck to see what attracted him. Dragons could adjust the focus of their eyes to either great distances or close inspection.

Something moved – away, the dragon said.

The gusts of his backwinging flattened grasses. Then F’lar saw the pin-sized, black-rimmed punctures of Thread on the leaves of the berry bushes. He stared hard, trying to discern the telltale evidence of burrows, the upheaval of soil, the consumption of the lush swamp greenery. The bush, the grass, the soil stood still.

“What moved?”

Something bright. It’s gone.

Mnementh landed, his feet sinking into the oozing terrain. F’lar jumped off and peered closely at the bush. Had the holes been made by droplets of hot Thread during a previous Fall? No. The leaves would long since have dropped off. He examined every nearby hummock of grass. Not a sign of burrows. Yet Thread had fallen – and it had to be this Fall – had pierced leaves, grass and tree over a widespread area – and vanished without a trace. No, that was impossible! Gingerly, for viable Thread could eat through wher-hide gloves, F’lar dug around the berry bush. Mnementh helpfully scooped out a deep trench nearby. The displaced soil teamed with grub life, writhing in among the thick tough grass roots. The unexpectedly gray, gnarly taproots of the bush were thick with the black earth but not a sign of Thread.

Mystified, F’lar raised his eyes in answer to a summons from the hovering weyrlings.

They wish to know if this is the Edge of Threadfall, Mnementh reported to his rider.

“It must be further south,” F’lar replied and waved the weyrlings in that direction. He stood looking down at the overturned earth, at the grubs burrowing frantically away from sunlight. He picked up a stout barkless branch and jabbed the earth of the trench Mnementh had made, prodding for the cavities that meant Thread infestations. “It has to be further south. I don’t understand this.” He ripped a handful of the leaves from a berry bush and sifted them through his gloves. “If this happened some time ago, rain would have washed the char from the punctures. The damaged leaves would have dropped.”

He began to work his way south, and slightly east, trying to ascertain exactly where Thread had started. Foliage on every side gave evidence of its passage but he found no burrows.

When he located drowned Thread in the brackish water of a swamp pool, he had to consider that as the leading Edge. But he wasn’t satisfied and bogged himself down in syrtis muds investigating, so that Mnementh had to pull him free.

So intent was he on the anomalies of this Fall, that he did not notice the passage of time. He was somewhat startled, then, to have T’bor appear overhead, announcing the end of Fall. And both men were alarmed when the ground-crew chief, a young fisherman from Ista named Toric, verified that the Fall had lasted a scant two hours since discovery.

“A short Fall, I know, but there’s nothing above, and Toric here says the ground crews are mopping up the few patches that got through,” T’bor said, rather pleased with the efficient performance of his Weyr.

Every instinct told F’lar that something was wrong. Could Thread have changed its habits that drastically? He had no precedent. It always fell in four-hour spans – yet clearly the sky was bare.

“I need your counsel, T’bor,” he said and there was that edge of concern in his voice that brought the other to his side instantly.

F’lar scooped up a handful of the brackish water, showing him the filaments of drowned Thread.

“Ever notice this before?”

“Yes, indeed,” T’bor replied in a hearty voice, obviously relieved. “Happens all the time here. Not many fish to eat Thread in these foot-sized pools.”

“Then there’s something in the swamp waters that does for them?”

“What do you mean?”

Wordlessly, F’lar tipped back the scarred foliage nearest him. He warily turned down the broad saw-edged swamp grasses. Catching T’bor’s stunned eyes, he gestured back the way he had come, where ground crews moved without one belch of flame from their throwers.

“You mean, it’s like that? How far back?”

“To Threadfall Edge, an hour’s fast walk,” F’lar replied grimly. “Or rather. that’s where I assume Thread Edge is.”

“I’ve seen bushes and grasses marked like that in these swampy deltas closer to the Weyr,” T’bor admitted slowly his face blanched under the tan, “but I thought it was char. We mark so few infestations – and there’ve been no burrows.”

T’bor was shaken.

Orth says there have been no infestations, Mnementh reported quietly and Orth briefly turned glowing eyes toward the Benden Weyrleader.

“And Thread was always short-timed?” F’lar wanted to know.

Orth says this is the first, but then the alarm came late.

T’bor turned haunted eyes to F’lar.

“It wasn’t a short Fall, then,” he said, half-hoping to be contradicted.

Just then Canth veered in to land. F’lar suppressed a reprimand when he saw the flame thrower on his half-brother’s back.

“That was the most unusual Fall I’ve ever attended,” F’nor cried as he saluted the two bronze riders. “We can’t have got it all airborne, but there’s not a trace of burrow. And dead Thread in every water pocket. I suppose we should be grateful. But I don’t understand it.”

“I don’t like it, F’lar,” T’bor said, shaking his head. “I don’t like it. Thread wasn’t due here for another few weeks, and then, not in this area.”

“Thread apparently is falling when and where it chooses.”

“How can Thread choose?” T’bor demanded with the anger of a frightened man. “It’s mindless!”

F’lar gazed up at tropical skies so brilliant that the fateful stare of the Red Star, low on the horizon, wasn’t visible.