The debt they owed, they insisted, could never be repaid. Until Tyl came aboard the hydrofoil one morning to see the patient.

  "There was a mooting." The temperature in the main cabin was seventy‑five and Homat sat shivering off in a corner.

  "What kind of mooting?" Lyra asked.

  "A community meditation. I am sorry thee were not in­vited, but there was no time. I have made the people aware of thy problem. Thy wooden undercarriage is still service­able, is it not?"

  "The wheels haven't fallen off, if that's what you mean," Etienne replied.

  "There are not here the large draft animals like the Mai have. No vroqupii. There are lekkas, but they are for riding, not for pulling. Unlike Turput, here the land is cultivated mostly by hand. But we are Tsla. The Tsla are strong." He flexed both arms and they saw the muscles ripple beneath short fur.

  "All Jakaie will assist. Will it not be easier to lower thy boat back to the bottom of the Barshajagad than it was to bring it up?"

  Etienne considered their guide's words, trying hard to restrain any excitement. Excitement hurt his back.

  "Sure it would be easier, but still a difficult descent."

  "I have talked long with Ruu‑an and the other elders. Them is a way north of here that descends to the Skar and bypasses the Topapasirut. They say also that the way is longer and gentler than that which climbs the side canyon we used. They say, Etienne and Lyra, that it can be done."

  "Who am I to dispute Ruu‑an?" said Etienne. He felt like shouting but restrained himself lest he strain something.

  "When can we start down?"

  "Soon. The families of those thee saved demand the honor of taking up the ropes nearest the spirit boat, where the work will be the hardest."

  "Our thanks go out to them," Etienne said.

  "Thee can thank them thyself." Tyl readied himself to leave. "It will take some time to organize provisions and find the rope sufficient to secure thy craft. Thee will have ample time to thank thy new friends and repair thy back."

  "Wait a minute," said Lyra, frowning. "What about the Na? What if they come back when the town is nearly de­serted, or catch everyone out in the open?"

  "This too was discussed during meditation. They will not come near Jakaie for a long time, so embarrassing to them was their defeat. And after a few days of descent the tem­perature will grow much too hot for them to follow us."

  "We won't argue with that, will we, dear?" He stared meaningfully at Lyra.

  As usual, she wasn't intimidated. "If the townsfolk feel confident of their security, I don't see why we shouldn't permit them to bounce you all the way down to the river."

  In contrast to the agonizingly difficult haul up from the bottom of the Barshajagad, the descent to a rocky beach northwest of Jakaie and the bulk of Aracunga mountain was almost relaxing. There were a few rough places, easily surmounted by the hydrofoil's repellers, but as the Tsla prom­ised the slope was far gentler than the steep side canyon route on the southern side.

  Chanting in unison as they leaned into the heavy ropes, the Tsla were able to lower the boat on its wheeled cradle faster than the Redowls expected. It was hard to imagine the vroqupii and their Brul doing the job any more efficiently than the citizens of Jakaie. It helped that there was none of the sense of competition among the townsfolk that there had been among the Mai. Homat grudgingly conceded that some­times cooperation was worth more than skill and strength.

  When at last the wooden cradle was removed from the hull and the boat bobbed once more in the waters of the Skar, Etienne passed among the villagers trying to thank personally each and every Tsla for their help.

  Ruu‑an chided him. "Too many thanks. If thee would truly thank us, thee may share thy knowledge with us when thee return this way. We will be waiting to take you up and past the Topapasirut a second time."

  No obstacles ahead to hold us back now, Etienne thought excitedly. No more blank spaces on the topographics, no second Topapasirut. According to the Mai, the Barshajagad began to widen once more north of that place. For the mo­ment they still floated between immense sheer walls, but now that the birthplace of river devils lay behind them the stark cliffs no longer seemed quite so forbidding.

  The seven of them reboarded and the Redowls settled into their boat with a sense of relief. It had become their home and refuge, and it was good to be surrounded once more by familiar objects and the comforts of an advanced technology.

  As Etienne let the boat float free in the current, the towns­folk assembled on the shoreline set up a plaintive, haunting chant of farewell, as different a music from the whirling frenzy of the Mai as Ligeti is from Gregorian chant. The swift current pushed the hydrofoil out into the center of the river.

  Lyra stood on the foredeck alongside Tyl, executing with him the Tsla posture of good‑bye. The song of farewell was beginning to fade with distance when Lyra turned and called to her husband. "Don't you think that's enough? Let's move." He made a face up at her. Suddenly she was concerned.

  "What do you think I'm trying to do?"

  She pressed her face to the plexalloy. "What do you mean you're trying?" They were accelerating steadily, but in the wrong direction. Only the boat's internal stabilizers kept them from spinning in helpless circles like a leaf caught in a flash flood.

  "Everything's functioning except the intake feed."

  "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 hoed 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 currant 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 orator 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 flush and blood would survive the coming con­cussion.

  The boat was enveloped ire 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 hold 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 stem.

  "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 ail," 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.

  It was not their existence or location that shocked the travelers, but rather the population‑Mai and Tsla traders and hunters mingled freely, working side by side with a lack of self‑consciousness that was stunning when compared to the uneasy peace maintained by their
southern relatives. The need to work together to survive in a harsh land had overwhelmed ancient suspicions and inhibitions. Homat and Tyl were startled as much by the implications as by the reality.

  "It bodes well for the future," Lyra commented. "Maybe when the Mai gain the technology that will enable them to live and work in colder climates and the Tsla the ability to move more freely through the humid river valleys, they'll discover this living example of racial cooperation waiting up here to show them the way."

  "They cooperate here in order to survive," Etienne ar­gued. "Without that external pressure, technological ad­vancement may only heighten ancient conflicts, not solve them."

  "You're such a damn pessimist!" she said angrily.

  He shrugged. "I look at things the way they are, not the way I want them to be."

  "And so do I, or are you making one of your frequent criticisms of my objectivity?"

  "It's just that it's so much easier to be objective about this." He hefted a sample of dark schist chipped from the riverbank where they had anchored inshore the day before. "On Earth this would be called precambrian or Vishnu schist. It's much older than its terran equivalent, however. There's nothing subjective about it."

  "Lucky you."

  "Nobody forced you into xenology. You chose it."

  "I sure did, because it's a damn sight more exciting and interesting when the subjects of your studies can talk back to you and help you with your research. Better that than a life of drudgery and dirt. My work provides me with new revelations every day."

  "All well and good, so long as you don't get personally involved with your revelations." Too late to retract, he thought furiously. Once more his mouth had moved faster than his brain.

  She eyed him strangely. "Now what's that supposed to mean?"

  He tried to escape into silence, stared at the rock walls about them. The cliffs on either side of the river were barely a thousand meters above the water now.