From behind the same corner came a duplicate of the first metal monster.

Another tracker.

Its drone rose into shrill crescendo. Like a dog, it approached the wreckage of its fellow. And like a dog, it summoned help. Then, without pausing to examine the mechanical casualty, it turned its electronic attentions back to the hunted.

Hopelessly, Newlin urged Songeen to her feet. They fled, and the game began all over again.

It was a madman's dream. Desperate flight, the haunted ruins of an unknown city, deadly pursuit closing in, slowly, patiently inevitably.

The familiar hare and hounds pattern of nightmare.

They fled through vague, littered streets, treacherous with the rubble of lost centuries. Buildings were lighter patterns upon the gathering darkness. Stone flagging underfoot was rough, eroded, rotten.

A pinnacled precipice rose suddenly to bar their way. Immense, sheer, b.u.t.tressed by spills of loose rock, it towered above them and lost its heights in gloom.

Within a ma.s.sive, deep-carved archway of stone, set an oval of polished red granite. A doorway, barren of carving save for one, scrawled and monstrous hieroglyph. Uneasiness stirred in Newlin, for something in his buried race-memories recalled that symbol with supernal dread. Ice formed about his spine and melted in trickling terror-drops. Instinct cringed, but his conscious mind rebelled at even the effort of memory.

Songeen stopped and stared at the hideously marked doorway, as if tranced.

"I _remember_ this place," she said in swift excitement. "But I had thought it vanished--eons ago."

Newlin swerved on her angrily. "This is no time for experiments with your subconscious," he growled, savage with strain.

"It is--sanctuary," she replied softly. "Come!"

Boldly she stood before the oval door. Her finger traced its complex symbol, and the symbol responded with a glow like moonfire.

Again, as it had been with that oval door in Monta Park, there was baffling suggestion of unmechanical movement.

The stone block did not slide, roll, or swing open. It gave a slight quiver and dissolved.

Songeen stepped through its aperture and the inner darkness of the building claimed her. Reluctantly, Newlin followed--caught as much by curiosity as driven by the yelping spectres of pursuit.

No light entered the building from any source. It was dark as the pits of Ganymede or the under-surface laboratories of Pluto. It was dense and tangible as a block of black crystal. Newlin could see nothing, not even Songeen. And there was an alien _feel_ to the interior.

He was aware that Songeen operated some hidden mechanism, and that the door, though he could not see it, was replaced.

"Now, for the moment, we are safe," she said slowly. "They cannot enter here."

Newlin shrugged bitterly. "It's all one. They can't enter and we don't dare go out. So we stay here and die of thirst. If you were really a top-rung witch, you'd think of details like air, food and water."

Songeen's laugh was a ripple of eery crystal in the darkness.

"How did you guess I was a witch?" she asked whimsically. "But we need not die here. Not unless you prefer to die among surroundings familiar to you. There is another way out. If we dare take it. For me, it will be simple. For you--"

"Not so simple, eh? You paint an interesting picture. Like one I once saw on Mars, in the Gneiss Gallery. 'Nocturne--Venusport,' it was t.i.tled. Beautiful. Dark purple background, the city seemed like fountains of flowering stars. It's not like that, not from the places I've seen it. Filth and dirt, people dying from poverty, disease or violence. Just a comparison. How close does your picture match the reality?"

"Close enough. You're a strange man, full of contradictions. I think you're only slightly mad. But for anyone, the way I could take you would be difficult. The pathway leads to my own world. To you--or anyone, not native--it will seem madness. Something of it you saw in the tower."

Around him in the darkness, he was conscious of her swift movements. She seemed untroubled by the lack of light. Neither by vision or hearing could he distinguish anything, but he sensed activity.

Then, suddenly, as if she had uncovered a cache of implements and struck a fire, radiance spread around her. Its source was not definite, and it spread slowly, like a stain through water. But something illuminated a vast, vaulted interior, Gothic in a sense, with a church-like air of gloom and mystery. It was Gothic, but of spiderweb delicacy, soaring arches, vague fretted ceilings, walls intricately carved into lacework of stone. Everywhere were echoes of that same eery symbolism in the door hieroglyph, and Newlin's folk-memories were oddly disturbed.

He could not place the feeling. Certainly none of the symbols bore even slight resemblance to any written language known to him.

Something about their intricacy clouded even clear perception, and the emotional effect was not religious in any sense--it was stark, abysmal fear, as if the mysteries behind such symbols were too great for humanity to bear.

Ignoring him, Songeen persisted at her curious tasks. Newlin went and stood beside her, watching.

With gloved hand, she appeared to be tracing out some maze of deep cut markings that figured what must have been an altar-fane.

"Do you expect any results from this ritual mumbo-jumbo?" he questioned irritably.

Songeen looked up, startled. "Not more ritual than any other mathematics," she chided. "This is no temple, as you seem to imagine. It is the old quarantine station. I seek a doorway, but not into a hidden pa.s.sage. There are other doorways. This one leads between dimensions. My world exists in a different plane. At least, our pathway to it follows strange ways, that you could never understand. You are no scientist or scholar. How could you grasp such unknown and forgotten matters? How could anyone in your world?"

Newlin stared at her, seeing things he had only guessed before.

"You are--_alien_," he said.

"You can't guess how alien," she answered. "I said I was not of Venusian stock. My people came from outside. Our world exists in the same plane as yours, a planet circling one of the nearer stars. This place was never our home, but we had colonies on Venus, Earth, Mars and one of Jupiter's moons. Other colonies--like this one--and observatories and quarantine stations. Our scientific observers and the medical staff stayed here. They studied and recorded and treated.

"We were not G.o.ds nor demons nor anything else supernatural. Just a people not human, but not too remote from humanity. Just emissaries and workers, students and doctors. You might call us elder brothers to the human race. We came not to conquer, enslave and exploit, but to help.

Sometimes the Masters came with us, since they were interested in our work.

"Many times, by our guidance, human beings reached high levels of development in the arts and sciences. We taught them and guided their stumbling steps, and released to them such knowledge as we dared trust to them. Time and again, we raised them from the slime, only to have them fall back. There is fatal disease in the race, a disease of instability and cruelty and violence. Call it madness--insanity--in the technical sense. It is pathological, and the disease is common to the human race, in all its ramifications. The Solar System is mad, and all who dwell in it are lunatics. Dangerous and homicidal lunatics. Sol's system is the asylum and pesthouse of our galaxy. We--my people--are its keepers and doctors.

"We are charged with the care and treatment of an ailing form of life.

Because of our near likeness, in form and thought, it was hoped that we could understand and help them; in time, perhaps, find a cure. There are other races inhabiting the galaxy--many of them, civilized, intelligent, living, and sometimes even of matter similar to ours. Their minds and bodies are too different. We are nearest, both in form and feeling.

"We have tried, patiently and hopefully. For the most part, it is a long history of frustration and failure. The corruption is too deep, too basic. It is part of the life-pattern of the race. Some individuals may rise above it, but its taint lies dormant even in them. At best, they are carriers. And there seems little future for such a race.

"Your galactic neighbors have been patient. But now a time of decision is near. Your ships explore, exploit at will within your system. You have pushed your limits to the furthest expansion of that system.

Colonized and despoiled. Now, you stand at the expanding horizon of stellar flight. Other star-systems tempt your imaginations, and technology batters at the problems involved.

"Your neighbors are watching, and afraid. If your people burst outside the limits of Sol's system, the contagion of your madness will spread and engulf the galaxy. At our request, they have given time, granting extensions freely. For countless centuries we have tried, and our effort, all our work and thought, has led only to failure. Now, the others have set a time limit, and the deadline is very close. Very close. You are all living on borrowed time; and but for our pleadings, it would be still less.

"The masters often send emissaries to us, as we send ours to the planets of Sol. They help and advise us--not as superior beings or as G.o.ds, commanding--but as elder brothers, trying to share their wisdom, trying to help and guide us. They only help and advise, never intervene unless asked. Their advice is wisdom--sometimes terrible, difficult to understand, painful to accept. Recently, they brought a message from the other peoples--a message and ultimatum. And the Masters advised us to accept failure, to let them destroy humanity as a blot on the galaxy. We begged one more chance, a last, desperate gamble, probably foredoomed to failure. But they granted us the painful right of the doctor. We can operate, but if the patient dies, so do we. That was our choice."

As she talked, Songeen had engaged herself busily with the queerly formal operations of tracing the intricate diagrams.

"Do you believe me?" she asked, looking up.

"I'm not sure," Newlin replied frankly. "Are these Masters your G.o.ds?"

"Not G.o.ds. Living, intelligent beings, civilized, but not like us. Not material. I cannot explain. Even they are but advisers and messengers.