"It is always so where Those Others have been. They leave behind them the thoughts which breed such dreams to trouble the sleep of those who are not of their kind. Let us go. I would like to be out of this place under the clean sky, where no ancient wickedness hangs to poison the air and thought."

Either the merman had miscalculated the direction of their route or the river mouth was much farther from the inland city than they had believed, for, though they pushed on for what seemed like weary hours, they came to no upward slope, no exit to the world they knew.

Instead Dalgard began to realize that just the opposite was true. At last he could stand it no longer and broke out with what he feared, hoping that Sssuri would deny that fear.

"We are going downhill!"

To his disappointment the merman agreed. "It has been so for the last thousand of our paces. It is my belief that this leads not to the sun but out under the sea."

Dalgard missed a step. To Sssuri the sea was home and perhaps the thought of being under its floor was not disturbing. The land-born human was not so prepared. If he had experienced discomfort under the river, what would it be like under the ocean? His terrifying dream of a lid being pressed down upon him flashed back into his mind. But his companion was continuing:

"There will be doors, perhaps into the sea itself."

"For you," Dalgard pointed out, "but I am no dweller in the depths."

"Neither were Those Others, yet they used these ways. And I tell you"--in his earnestness the merman laid his hand once more on Dalgard's arm--"to turn back now is out of the question. The death which haunts the darkness is still sniffing out our trail."

Dalgard glanced involuntarily over his shoulder. By the faint and limited light of the purple disks he could see little or nothing. An army might creep there undetected.

"But--" His protest was in answer to the merman's seeming unconcern.

Sssuri at the first intimation that the hunters were behind them had shown wariness. Now he did not appear to care.

"They had fed," he replied. "Scouts follow because we are something new and thus suspect. When hunger rises once more in them, and their scouts report that we are meat, then is the time to draw knives and prepare for battle. But before that hour we may have won free. Let us search for the gate we now need."

However confident the merman might be, Dalgard could not match that confidence. In the open air he would have faced a snake-devil four times his size without any more emotion than a hunter's instinctive caution. But here in the dark, unable to rid himself of the belief that thousands of tons of sea water hung over his head, he found himself starting at any sound, his knife bare and ready in his sweating hand.

He noted that Sssuri had stepped up the pace, pa.s.sing into his sure-footed glide which made Dalgard exert himself to keep up. Before them the corridor stretched without a break. The merman's promised exit, if it existed, was still out of sight.

It was difficult to gauge time in this dark hall, but Dalgard thought that they were at least an hour farther on their way when Sssuri paused abruptly once more, his head c.o.c.ked in a listening att.i.tude, as if he caught some whisper of sound too rarefied for his human companion.

"Now--" the thought hissed as if he spat the words, "they hunger--and they hunt!"

He bounded forward with a spurt, which Dalgard copied, and they ran lightly, the dust undisturbed in years puffing up beneath the merman's bare, scaled feet and Dalgard's hide boots. Still the unbroken walls, the feeble patches of violet in the ceiling. But no exit. And what good would any exit do him, Dalgard thought, if it opened under the sea?

"There are islands off the coast--many islands--" Sssuri caught him up. "It is in my mind that we shall find our door on one of those.

But--run now, knife brother, for those at our heels awake and thirst for flesh and blood. They have decided that we are not to be feared but may be run down for their pleasure."

Dalgard weighed his knife in his hand. "They shall find us with fangs," he promised grimly.

"It will be better if they do not find us at all," returned Sssuri.

A burning arch of pain encased Dalgard's lower ribs, and his breath came in gusts of hastily sucked air as their flight kept on, down the endless corridor. Sssuri was also showing signs of the grueling pace, his round head bent forward, his furred legs pumping as if only his iron will kept them moving. And the determination which kept him going was communicated to the scout as a graver warning than any thought message of fear.

They were pa.s.sing under one of the infrequent violet lights when Dalgard got something else--a mental thrust so quick and sharp it was as if a sword had cut through the daze of fatigue to reach his brain.

Yet that had not come from Sssuri, for it was totally alien, wavering on a band so near the extreme edge of his consciousness that it p.r.i.c.ked, receded, and p.r.i.c.ked again as a needle might.

This was no message of fear or warning, but of implacable stubbornness and ravening hunger. And in that instant Dalgard knew that it came from what was sniffing out their trail, and he no longer wondered that the hunters were immune to other mental contact. One could not reason with--that!

He spurted forward, matching the merman's acceleration of speed. But to Dalgard's horror he saw that his companion now ran with one hand brushing along the wall, as if he needed that support.

"Sssuri!"

His thought met a wall of concentration through which he could not break. In a way he was rea.s.sured--for a moment, until another of those stabs from their pursuers struck him. He longed to look back, to see what hunted them. But he dared not break stride to do that.

"Ahhhh!" The welcoming cry from Sssuri brought his attention back to his companion as the merman broke into a wild run.

Dalgard summoned up his last rags of energy and coursed after him.

Sssuri had halted before a dark lump which protruded from the side of the corridor.

"A sea lock!" Sssuri's claws were clicking over the surface of the hatch, seeking the secret of its latch.

Panting, Dalgard leaned against the opposite wall. Just as a protest formed in his mind he heard something else, the pad of feet, many feet, echoing down the corridor. And somehow he was able now to look.

Round spots of light, dull, greenish, close to the ground, as if someone had flung a handful of phosph.o.r.escence into the dark. But this was no phosph.o.r.escence! Eyes! Eyes--he tried to count and knew it was impossible to so reckon the number of the pack that ran mute but ready. Nor could he distinguish more than a very shadowy glimpse of forms which glided close to the ground with an unpleasant sinuosity.

"Ahhhhh!" Again Sssuri's paean of triumph.

There was the grate of unwilling metal forced to move, a puff of air redolent with the sea striking their bodies in chill threat, the brightness of violet light stepped up to a point far beyond the lamps in the corridor.

With it came no rush of drowning water as Dalgard had half expected, and when the merman clambered through the hatch he prepared to follow, well aware that the eyes, and the pattering feet which bore them, were now almost within range.

There was a snarl from the pa.s.sage, and a black thing sprang at the scout. Without clear sight of what he was fighting, he struck down with his knife and felt it slit flesh. The snarl was a scream of rage as the creature twisted in midair for a second try at him. In that instant Sssuri, leaning halfway out of the hatch, struck in his turn, thrusting his bone knife into shadows which now boiled with life.

Dalgard leaped for the lock door, kicking out swiftly and feeling the toe of his boot contact with a crunch against one of those darting shades, sending it back end over end into the press where its fellows turned snapping upon it. Then Sssuri grabbed at him, bringing him in, and together they slammed the hatch, feeling it shake with the shock of thudding bodies as the pack outside went mad in their frustration.

While the merman fastened the locking bar, bringing out of the long-motionless metal another protesting screech, Dalgard had a chance to look about him. They were in a room some eight or nine feet long, the violet light showing up well tangles of equipment hanging from pegs on the walls, a pile of small cylinders on the floor. At the far end of the chamber was another hatch door, locked with the same type of bar as Sssuri had just lowered to seal the inner one. The merman nodded to it.

"The sea--"

Dalgard slid his knife back into its sheath. So the sea lay beyond. He did not welcome the thought of pa.s.sing through that door. Like all of his race he could swim--perhaps his feats in the water would have astonished the men of the planet from which his tribe had emigrated.

But unlike the mermen, he was not sea-born, nor equipped by nature with a secondary breathing apparatus to make him as free in the world of water as he was on land. Sssuri might crawl through that hatch without fear. For Dalgard it was as big a test as to turn and face what now raged in the corridor on the inner side.

"There is no hope that they will go now," Sssuri answered his vague question. "They are stubborn. And hours--or even days--will mean nothing. Also they can leave a guard there and rove at will, to return upon signal. That is their way."

This left only the sea door. Sssuri padded across the chamber and reached up to free one of the strange objects dangling from the wall pegs. Like all things made of the marvelous substance used by Those Others for any article which might be exposed to the elements, it seemed as perfect as on the day it had first been hung there, though that date might be a hundred or more Astran years earlier. The merman uncoiled a length of thin, flexible piping which joined a two-foot canister with a flat piece of metallic fabric.

"Those Others could not breathe under the water, as you cannot," he explained as he worked deftly and swiftly. "Within my own memory we have trapped their scouts wearing aids such as these so that they might spy upon our safe places. But their last foray was some years ago and at that time we taught them such a lesson that they have not dared to return. Since they are not unlike you in body and since you breathe the same air aboveground, there is no reason why this should not take you out of here."

Dalgard accepted the apparatus. A couple of elastic metal bands fastened the canister to the chest of the wearer. The fabric molded into a perfect, tight face mask as it touched the skin.

Sssuri went to the pile of cylinders. Choosing one he tinkered with its pointed cone, to be rewarded with a thin hiss.

"Ahhhh--" again his recognition of the rightness of things. "These still contain air." He tested two more and then brought all three back to where Dalgard stood, the canister strapped into place, the mask ready in his hand. With infinite care the merman fitted two of the cylinders into the canister and then was forced to set the other aside.

"We could not change them while under water anyway," he explained. "So it will do little good to take extra supplies with us."

Trying not to speculate on the amount of air he could carry in the cylinders, Dalgard fastened on the mask, adjusted the air tube, and sucked. Air flowed--he could breathe! Only--for how long?