“Dammit!” She rushed for the nearest gangway.

As she looked aft she saw the canyon narrowing further behind them, forming the immense granitic funnel which Etienne had theorized constituted the upper limits of the Topapasirut. In the distance and coming rapidly closer she could make out thickening mist and the first faint, threatening rumble of water attacking rock. She dropped through the gangway and in seconds stood alongside her husband.

“Everything checks out, everything. Except the intake feed. Every time I try to open her wide she locks shut on me.”

“Emergency override?”

“Forget it. I’m still trying, though.”

“Repellers?”

“No way. We used our stored power during the descent from Jakaie. We need time to recharge or else we can recharge by moving Upriver. Of course, if we could move Upriver we wouldn’t need to recharge.” He worked rapidly at the diagnostic computer, canceling unhelpful replies to his queries. Unfortunately, those were the only type of reply he could extract.

The rumbling astern was becoming thunder. Dense mist enveloped the narrow cleft of the canyon. He switched the stern scanner to sonic and tridee black-and-white graphics appeared on the screen as ultrasound penetrated the obscuring mist. In a very few minutes the current would slam the helpless boat into the unyielding sheer cliff that was the upside-down waterfall, the Topapasirut. Fragments of the hydrofoil would boil out of the water Downriver, to be wondered at by any Mai who encountered them on nameless beaches. Of the crew there would be only a memory. Nothing so fragile as flesh and blood would survive the coming concussion.

The boat was enveloped in a storm as the river rained toward the sky.

“Do something!” Lyra shouted above the crash of the water.

“Do something yourself!”

She eyed him a moment before turning to disappear below. Her voice reached him via the engine room intercom.

“Everything looks okay. The fuel cells are produc—”

“I can see that on the readout!”

“Just letting you know what I see down here. The engine’s quiet, and—wait a minute.”

“That’s about what we’ve got left.” The boat vibrated anxiously beneath his feet. Would they know when they hit the cliff? He couldn’t begin to calculate their velocity.

“Try it now!” Lyra ordered him.

He ran numbly through the restart procedure, was startled when the Function light turned green. He stabbed the accelerator, bringing thrust up to maximum.

For an eternity they hung motionless in the vortex, suspended in fog between open water and oblivion. Then very slowly the hydrofoil began to creep Upriver. To Etienne their progress seemed infinitesimal. His anxiety was heightened by the knowledge that whatever had shut down the flow of water to the jet once could do so again at any moment. Gradually their velocity increased to the point where the boat could rise up on its hydrofoils. As the river fell away beneath the hull, relinquishing its grasp, they started to make some real speed. Thunder faded behind them.

As they left the mist Lyra emerged from belowdecks. Her hair was strung like paint across her face, alternating with rivulets of sweat. She stank of Skar.

“What did you do down there?” He spoke without looking at her, refusing to take his eyes off the controls lest something else fail before they were out of danger.

“Emergency surgery.” She slumped into a seat. “Very complicated.” She held up something in her right hand. As he turned to look he saw that she was wearing heavy-duty insulated work gloves.

A half dozen glistening worms twisted in her grip. They had dark heads.

“These were glued to the conduit just above the main feed to the jet. Watch this.” She held up a small diagnostic probe with her left hand, touched it to the tail of one worm. A loud buzzing filled the cockpit and the readout on the front of the tool went berserk.

“Local relative of the terran gymnotids. Generates quite a current for its size. They must have thought they’d found themselves a nice new home when they slipped in through the mesh intake strainers on the foils. Every time you ordered the boat to open the intake feed they responded with a corresponding jolt. No wonder the computer couldn’t locate the source of the short-out in the system. It was external. You’d order the feed opened and these little cuties would short it shut, countermanding the directive.”

She rose and turned to open one of the ports in the cockpit. With great deliberation she flung her slimy acquisitions as far out into the river as possible. Then she closed the port and spoke toward the stern.

“You can come out now, Homat.”

Hesitantly their Mai guide emerged from the heated storage locker in which he had secreted himself. “We’re not going to die, de-Lyra?”

“No, we’re not going to die. Not today, anyway. The spirit boat is functioning normally again.”

He crept out to join them, still encased in his cold-weather gear to combat the cabin’s air conditioning. Soon that air conditioning would no longer be required. That would be no comfort to Homat, who would continue to pile on clothing the nearer they drew to Tslamaina’s arctic circle.

The population of Jakaie was still assembled along the riverbank. As the spirit boat reemerged from the mouth of destruction, alien voices expressed relief. The villagers lined up quickly and once more the occupants of the hydrofoil were treated to the chant of farewell as Tyl and his companions performed the gestures of good-bye.

“Calm acceptance,” Lyra murmured, “no matter what our fate.” She was standing on the foredeck alongside their Tsla friends. “Tell me, Tyl, what would the reaction have been if we hadn’t come back out?”

“There would have been no reaction that thee could have seen, save that after a suitable time they would have begun a funeral chant instead of one of farewell.”

“There didn’t seem to be any panic as we slipped downstream.”

“Why should there be? There was nothing they could do to help us,” he explained patiently. “Thee should know, Lyra, that we are not given to violent displays of emotion in public.”

“I recall. Would any of them have grieved for us in private?”

“I imagine so. But they could do nothing to help us.”

“Just as nothing could be done to help those who’d been taken by the Na.” Etienne spoke from inside the cockpit, addressing his wife in terranglo. “I don’t care what the level of mental serenity is among these people, they’re not going to make much progress until they dump this fatalism. If they don’t watch out, the Mai are going to push forward to develop a complete, advanced technological civilization. The Tsla will end up becoming wards of the Mai, just as it will be the Mai who will push out to tame the Na and the Guntali.”

“Specious argument for radical change,” Lyra shot back. “The Tsla are content as they are, much happier than the Mai.”

“Sure, and the ancient Polynesians were happier and more content than the caucasoids who ministered among them, and we remember what happened to their culture.”

“Etienne, the analogy doesn’t apply here. The Tsla are a different race, occupying a radically different ecological niche. It’s not the same thing at all.” And she launched wholeheartedly into a lengthy dissertation on history and anthropology that both Homat and Tyl desperately wished they could understand.

Upriver, according to the best information available to Ruu-an and the elders of Jakaie, two last immense tributaries fed into the Skar: the Madauk and the Rahaeng. Beyond that lay the far narrower but still impressive Upper Skar, and unknown lands.

Several hundred kilometers above the Topapasirut the geology of the land altered radically. The gorge of the Barshagajad widened and the river rose in frequent steps, reducing the depth of the canyon. The Redowls were constantly being wakened from sleep by the insistent beeping of the computer. Since the boat could not negotiate rapids on autopilot, Etienne or Lyra would stagger sleepily forward to run the whitewater or lift the hydrofoil past it on repellers.

The steady rumble of the rapids was in stark contrast to the silent river south of Aib. At night Tslamaina’s four moons transformed the streaks of white water into thousands of pale crystalline tentacles. Not all was difficult, however. There were quiet stretches of relatively calm water of great beauty.

They began to relax for the first time since leaving the Skatandah. As the temperature grew chillier and the river climbed its ancient bed they encountered fewer signs of settlement, as the land was fit only for Mai hunters and gatherers. Occasionally they saw a few ramshackle houses clustered around poorly irrigated plots. No elaborate terraces had been built there.

Shaped by a harsh land, the local Mai were a hardier breed than their southern cousins. They were also open and much more honest. Or perhaps they were just so startled by the appearance of the hydrofoil and its strange inhabitants that the urge to thieve never crossed their minds.

“I’m not sure that’s it at all,” Lyra theorized one day. “The truism seems to hold among nonhuman primitives as well as among our own kind that the poorer the people and the more isolated their homes, the more trustworthy and helpful they are. Hardship seems to breed a need for companionship which extends to lending assistance to any who come your way.”

Etienne did not argue with her because he was more interested in the locals’ openness and lack of fear. They were startled but there was none of the fearful paranoia or jealous awe the Redowls had encountered farther south. He surmised it was because everything was new to these pioneers. For all they knew the Redowls came not from another world but from some unknown distant city-state bordering the Groalamasan. When one shares a world with two other intelligent races it’s not difficult to accept the existence of a third.

They expected to encounter a few Tsla villages, but Ruu-an told them to expect none, and the information supplied by the elders of Jakaie turned out to be accurate. Whether the abandonment of the northern latitudes by the Tsla was a decision of choice or due to some unknown circumstances, Lyra could not determine. Homat and Tyl argued about it long into the nights, with the Mai staking a claim for greater adaptability among his kind and Tyl retreating into calm conviction that a perfectly good reason existed for shunning such a barren land.

A considerable surprise awaited everyone aboard the boat, however, when they reached the confluence of the three great rivers. Where the Madauk and Rahaeng joined their volume to that of the Skar, several small villages had grown, trading posts, no more.