Actually they had started out by vehicle. But it was old, cranky and ready for the junkyard. In the first flurry of sandstorm, it had clogged, burned out and died. Nothing very reliable was available in the black market without more notice.

Newlin accepted the inevitable and proceeded on foot. Perhaps they could reach the Archaeological Station at Sansurra. He was not certain if it would be inhabited at the Sandstorm season, but there was a good chance of stored food and water. Turning back to Venusport was impossible. So they went on.

Now he was confused. Directions are difficult at best on Venus, and his radio-compa.s.s proved faulty. He had only the vaguest idea where they were, and none at all where they were headed. But if he stopped too long, the shifting dunes would cover them. And if they tried to go too fast, it would be fatally easy to blunder into one of the open sink-holes of molten, radioactive metal.

He stopped and motioned the girl to rest.

She sank down, exhausted.

Newlin adjusted the throat microphones and headsets in their plastic helmets to make for easier conversation. But for a while, neither could talk. They sat and gasped, yearning for a breath of fresh, unreclaimed air. Water supplies were low, and already Newlin had established iron rations. Drinking by tubes was difficult in the helmets and the water was warm and foul.

"You're lost?" Songeen asked at last.

Newlin nodded. He produced a wrinkled, battered map. "I can't even trust the compa.s.s. I don't know where we are."

The girl took the map in her gloved hands and peered intently through her face-mask. One finger traced a tiny circle in the film of dust.

"I know," she said. "We are somewhere about here. And over there--" she indicated a direction behind Newlin--"is the city from which my people came."

Newlin was startled. The directional instinct with which all Venusians are endowed was familiar enough, yet he would have sworn the girl was not from the enfeebled and mutant races of the veiled planet. She was, at once, more human--and more remote. Songeen guessed his doubt. Through the fused quartz faceplate, her angular features wore a curious, faint smile.

"No, not Venusian. This was an--an outpost. A colony and a quarantine station. The city was abandoned long ago. Long before the atomic holocaust my people fled. Eons have pa.s.sed. Everything is now in ruins--if even ruins remain. See, it is not marked on the map. Not even as ruins. But we have unusual race-memory. I can see the fabulous towers and a.r.s.enals, the terraced gardens and the palaces--as if they still stood today as they were in that vanished yesterday. And we have the homing instinct. It was my people who gave it to the Venusians. The one thing of value that still remains to them."

Newlin was still dubious. "Unless you're dreaming."

Her finger jabbed at the map. "We are here," she insisted. "And if you care to search and dig, the city is probably still there, as it was a million years ago."

"Would there be water in your ruined city?" Newlin asked.

"Who knows? The wells are probably all filled with sand now. Or gone dry, or become contaminated. There is always much radioactivity near the ruined cities. They were primary targets when the peoples of Venus destroyed themselves. Even this desert is mute evidence of the holocaust; if one needs evidence. My people fled before that madness, because they antic.i.p.ated it."

Newlin snorted. The pre-holocaust Venusians were purely legendary. No written records could exist, amid such conditions as must have followed the ancient wars. Science knew that at least half a million years had pa.s.sed since Venus was a fair green planet peopled with hearty, beautiful, ease-loving races. Half a million years since the surface people had even looked upon the sun.

"If you're right about where we are," Newlin growled, "I'm still interested in that city. We can never make Sansurra with the water we have. Ruined or not, there may be wells. Is there a chance?"

"Not a good one," Songeen replied. "But better than none."

"Whenever you're ready," Newlin said. "You lead."

Wearily, man and girl struck off across the seas of shifting sand. Great dunes blocked their way. Some they circled, others must be climbed laboriously.

From the top of a huge, wind-ribbed billow, Newlin stared at a pale flickering in the dust ahead. In all other directions stretched endless humps and hollows. But before him lay a great wind-scoured hollow of bare rock. Beyond that, crowning a series of low hills, which must have thrust above water line in this shallow part of the ancient, vanished sea, were ruins.

Even as ruins, the city was spectacular. Ma.s.sive columns had eroded slowly into stone toothpicks. Walls crumbled into formless heaps resembling the dunes. A few outlines of smoothed blocks and shattered lintels huddled the ground, half hidden by the encroaching sand. Details had vanished eons ago, but something still remained to tantalize imagination. The few buildings that still stood, and the soaring, fragile towers evidenced an engineering civilization of staggering proportions. Surface dimensions were still tremendous, and the city itself must have been of first importance, covering hundreds of square miles.

"Our city," said Songeen.

Newlin glanced quickly behind. Still distant, but moving very rapidly was the string of dark objects that could only be sandsleds of the pursuit. One tiny figure, scarcely visible, was far in advance of the others. The robot tracker.

He gestured. "They're covering three miles to our one," he told her grimly. "We'll try to reach the city before they catch up with us.

Perhaps we can hide out among the ruins, and--with luck, b.o.o.by-trap the tracker. If there's water, we can hold out for quite a while."

Songeen nodded crisply. Her voice was strained with emotion and fatigue.

"As fugitives my people abandoned this city. Now, as a fugitive, I return."

Then she was off, running awkwardly, the c.u.mbersome suiting of her protection armor giving her bounding strides the laughable appearance of a lumbering teddy-bear.

Descent into the hollow was riding a series of miniature sand avalanches. Each step buried the foot deep, but the sand gave way and slipped in loose spills. His boots struck hard on rough, bare rock. He grunted, fought for balance, then sprawled heavily. She helped him up, then took off again. Newlin followed.

Over the wind-carved rock, they made good time. Ascent of the long, jagged slopes to the city was heart-killing work, delicate and treacherous. The surface was like sponge-gla.s.s, brittle and deadly with knife-edges when broken.

Sheltering from wind-driven sand under the cover of a great monolith, Newlin and Songeen watched the racing figures of pursuit top the crest of the opposite ridge and start down. Man and girl were too winded and weak even to get up. They dared rest only a moment, then plunged on into the maze of tumbled ruins. Ultimate exertion had taken toll of their energies and rapidly burned up air reserves. Both were cruelly thirsty.

The heat, even inside their insulated suits, was stifling.

There was no time to take stock of manifold discomforts.

The race was neck and neck. Death sniffed at their heels in the guise of mechanical trackers. On Venus, life is to the swift and cunning. To Newlin, life was perilous, but sweet.

Their helmet microphones picked up and amplified a curious droning buzz.

It was the deathsong of the electronic tracker and it seemed closer than it was.

Slowly, inexorably, it grew louder. Sound swelled steadily, and it was a whiplash to their flagging energies. They fled in panic through the streets of the dead city.

It was no real refuge to them, but its megalithic precincts gave some lying illusion of safety. They chose a twisting, tangled route into the very heart of the ruined city, with the instinct of a hunted animal to confuse its trail. They doubled back to cross their own trail twice, in the vain hope of baffling the electronic enemy.

Newlin had been hunted before, on Mars, but by live bloodhounds. Pepper, oil of mustard, and perfumes had saved him then. But this hound followed not scent, but something intangible, electrical, and as mysterious as the soul-aura itself. It sorted two life-complexes from all other impulses and followed its own prime-directive--hunt down and kill.

The end was inevitable as death.

Newlin laid ambush for the mechanical monster. Crouched in a nest of rubble, he waited for it, blaster gun ready. Around a corner of shattered stones, it appeared. It moved like a whipping shadow, like part of the gathering twilight.

Silent, save for the high, nerve-tearing drone, it came warily across the courtyard paved with eroded stone. It was low, not animal in appearance, with the form of a fat, ugly snake. Fading light of the Venusian day cast a glint of metallic gray from its scaling of interlocked rings.

Newlin waited for a close shot. How vulnerable was such a soul-less, mechanical monster to even the shattering-heat-forces of a blaster gun?

Songeen lay quietly beside him, her body quivering as much from strained muscles as from fear. Behind the face-mask, her thin features were pale, ghostlike.

With elaborate caution, the tracker circled their hiding place. Its froglike head, with a ruff of exposed filaments lifted, like an animal scenting blood. It edged slowly closer, its movement a glide, sinuous, crafty, with no suggestion of mechanical action.

Newlin pushed the girl's form roughly away, lest her trembling foul his aim. Sighting, he pressed trigger. Bright flame leaped from the weapon, crackling.

The beam lashed at the tracker, which stopped suddenly, threw back its monstrous head, and burst into hideous uproar of sparking, electrical discharge. Like a live thing, it twitched, jerked, and flung itself in mad spasms. Convulsions stopped as short-circuits flared in both head and body. Molten, flowing, its metallic carca.s.s glowed eerily in the dimness. Dying, it blazed up in a fireworks display spectacular enough to attract half of Venus to the terrified fugitives.

But the drone continued.