The landing had been uneventful, which was fortunate, since nobody aboard the ship had any useful experience of landing on a planet whose atmosphere, geology and history were almost entirely unknown. The descent had been conducted automatically for the most part, with {{user}} supervising the approach from the pilot's station while Elira watched the navigational data and Korrin kept one eye on the atmospheric readings and the other on the weapons systems. There had been no storms, no unexpected turbulence and no interference with the ship's instruments. The planet had accepted their arrival with complete indifference.

Now the ship stood on its landing struts in a shallow depression between two ridges of dark, fractured stone. Its engines had been shut down several minutes earlier, and the cooling systems produced the only mechanical noise in the immediate vicinity: occasional clicks and metallic contractions from the hull, accompanied by the low, almost inaudible circulation of air through the environmental systems. Beyond the ship there was nothing that resembled a road, a settlement or even a recognisable geological feature. The plain stretched away beneath a sky of unusual colour, greenish-yellow near the horizon and gradually darkening toward a deep blue overhead. A broad, pale band crossed the western sky, but it was impossible to determine from a distance whether it was cloud, suspended dust or something more artificial.

Elira Vey stood at the bottom of the landing ramp with her helmet tucked beneath her arm and an atmospheric analyser in her other hand. She had been watching the horizon for several minutes, apparently expecting the landscape to reveal something through prolonged observation. It did not. The instrument gave her a sequence of readings, corrected itself twice and finally settled into a range which, by human standards, was sufficiently harmless.

"Atmosphere is breathable," she said. "There are some compounds I don't recognise, but they're present in concentrations too low to matter. Pressure is slightly below terrestrial standard, temperature is comfortable, and there doesn't appear to be anything immediately toxic."

Korrin Dask descended the ramp behind her. He was already wearing his exploration suit, although he had left the helmet open, and the weapon mounted across his chest gave him the appearance of a soldier who had wandered into the wrong expedition. He was considerably larger than Elira, broad through the shoulders and arms, and possessed the sort of physical confidence that made him occupy more space than was strictly necessary.

"That's the scientific version of 'we're not going to die as soon as we take our helmets off,'" he said.

Elira looked at him.

"It's the accurate version."

"Which is usually less satisfying."

She smiled faintly and returned her attention to the landscape.

There was very little vegetation, although calling it vegetation was already an assumption. Low clusters of dark, flexible stems emerged from the soil at irregular intervals, each ending in a translucent sphere approximately the size of a human fist. They reflected the light strangely. At one angle they appeared almost black, while from another they became faintly violet and seemed to contain a cloudy substance suspended within them. Nothing moved among them. There were no insects, birds or small animals, and no sound came from the vegetation itself.

Elira crouched beside one of the clusters and brought the analyser closer.

"I don't think we've established that these are plants."

Korrin glanced down.

"They look like plants."

"So do some things on Earth that aren't plants."

"Everything looks like something on Earth eventually."

"That's exactly the problem."

He crouched beside her and studied the nearest stem. He did not touch it. Korrin was an engineer by profession and inclination, but even he had enough sense not to put an unprotected hand on the first unidentified organism they encountered on another planet.

The silence bothered him more than he cared to admit. It was not simply that the landscape was empty. Earthly landscapes possessed a constant background of movement: insects, birds, wind through leaves, distant machinery, water, animals hidden beyond the immediate field of view. Even places described as silent were full of sounds once one paid attention to them. Here there was almost nothing. The air moved occasionally against the surface of the ship, but otherwise the planet seemed to be holding itself perfectly still.

It was difficult to reconcile that stillness with what they already knew.

There was life here.

That fact had been established before they left Earth, although establishing it had required an instrument that had itself raised considerably more questions than it had answered.

The Oculnicus Mark III had been built inside a heavily protected scientific facility somewhere beneath the Earth's surface. Its existence was known to very few people, and even fewer understood the principles behind it. The machine was not a telescope, despite the misleading descriptions sometimes used by people outside the project. It did not magnify distant objects or gather electromagnetic radiation. Its central component was a transparent crystalline structure held within a complex arrangement of magnetic and gravitational fields. The crystal had no accepted classification and, as far as anyone knew, had no natural counterpart.

The Oculnicus had been designed to look beyond ordinary space.

The original theory had been concerned with extremely distant locations, but the machine behaved in ways its designers had not predicted. Under certain conditions it seemed capable of observing locations separated from the observer by more than distance. Some experiments suggested that it could see into different temporal states; others suggested alternate physical histories or parallel worlds. None of the competing explanations had survived every test, and the scientists responsible for the project had eventually adopted the least satisfying description possible: the Oculnicus allowed them to observe places that could not otherwise be observed.

Its operation required an extraordinary amount of energy. A single observation involved weeks of preparation and the coordination of equipment occupying an entire underground complex. The Mark III could not simply be switched on whenever somebody became curious about another planet. The power requirements were too great, the equipment too delicate and the consequences of an uncontrolled experiment too poorly understood.

The observation that had led them here had lasted less than a minute.

It had been repeated under increasingly controlled conditions until the scientists were satisfied that what they were seeing was not an artefact of the machine.

They had found a planet.

They had found structures.

And, on several occasions, they had found indications of life.

That was the part nobody had been able to explain.

The Oculnicus did not identify organisms. It did not provide biological classifications or conveniently label objects for its operators. It merely produced an image, and the image had contained movement in several locations. Something had appeared to travel through one of the structures. Something else had disappeared beneath the surface. On another observation, a series of lights had appeared in an apparently abandoned complex and then vanished again.

The scientists could not determine whether they were looking at animals, machines, remnants of some automated system or inhabitants of the planet itself.

The expedition had therefore been authorised with a deliberately broad objective: locate the source of the observed activity and document as much of the planet as circumstances permitted. They were not to establish contact unless contact became unavoidable or clearly safe. They were not to interfere with unfamiliar systems without good reason. They were to collect samples, record observations and return with enough information to allow the scientists on Earth to make sense of what the Oculnicus had shown them.

Nobody had been able to tell them what kind of life they were looking for.

Korrin stood up and brushed dust from his gloves.

"So," he said, looking toward the distant structures, "we've got an inhabited planet with no visible inhabitants."

Elira rose beside him.

"We don't know that it's inhabited."

"The Oculnicus detected something."

"It detected something that might be alive."

"That's usually what people mean when they say detected life."

"It detected something which behaved in a way consistent with life."

Korrin gave her a sideways look.

"You're making the distinction because you expect us to discover something unpleasant."

"I'm making the distinction because we don't know what we're looking for."

He considered this for a moment and nodded. "Fair."

Their attention had been drawn toward a dark line crossing the plain several metres from the ship. From a distance it could have been a natural depression, but as they approached it became clear that its edges were too regular. Two parallel strips of an almost black material emerged from beneath the soil and continued toward the distant structures, maintaining their separation with remarkable precision.

Elira brought up the sensor display on her wrist.

"There's a field here."

"What sort?"

"I don't know."

Korrin crouched and examined the surface. The material was smooth but not reflective, with a texture that seemed to alter slightly as the light moved across it. It resembled neither stone nor metal. There were no visible joints, bolts or seams.

"Could be a road," he said.

"Could be."

"It could also be part of a machine."

"Yes."

"Or a boundary."

"Yes."

"You're enjoying this, aren't you?"

Elira looked at him with an expression of mild amusement.

"Perhaps a little."

Beyond them, the largest structure in sight dominated the horizon. It had been visible from orbit, although its scale had been difficult to appreciate from above. Now that they stood on the surface, its proportions became increasingly difficult to comprehend. Several immense vertical masses rose from the plain, apparently joined by structures that extended between them at different heights. Some surfaces were pale and smooth, others dark and heavily weathered. There were openings which might have been entrances, although none appeared large enough to provide a sensible explanation for the scale of the building itself.

The whole thing had the appearance of architecture without quite behaving like architecture.

There was no obvious symmetry, but there was unmistakable order. Nothing seemed to have been placed randomly. Even the portions that appeared damaged retained geometrical relationships that suggested the original builders had worked according to principles the human eye could only partially recognise.

Elira studied the structure through her visor.

"That's probably our best starting point."

Korrin followed her gaze.

"Probably."

"You disagree?"

"I think the enormous alien structure is exactly where an enormous alien expedition should go."

"That's not a scientific argument."

"No, but it's a good one."

They began preparing their equipment.

Their instructions from Earth had been precise about some things and remarkably vague about others. They were to investigate the world, but they had no map detailed enough to tell them where they should begin. They were to find the life forms, but nobody could tell them whether the things they found would breathe, think, reproduce, communicate or even possess bodies. They were to learn about the civilisation that had left the structures behind, although there was no evidence yet that the builders and the detected life forms were the same thing.

The uncertainty was almost complete.

That was what had attracted {{user}} to the mission in the first place, although none of them had said so quite so plainly. Humanity had spent centuries travelling outward through space, gradually replacing the unknown with charts, measurements and databases. Even the most distant worlds were becoming catalogued. Their atmospheres could be analysed before a ship arrived, their surfaces mapped from orbit, their resources identified and their climates predicted.

This world had resisted all of that.

The Oculnicus had shown them a place where their existing knowledge was insufficient.

Now they had to find out why.

Korrin sealed his helmet and checked the rifle indicator one last time. Elira did the same, then adjusted the medical equipment secured around her waist.

The ship remained behind them, small against the empty landscape, its landing lights illuminating a few metres of dark ground beneath the hull. Everything beyond that circle of artificial light belonged to the planet.

Somewhere out there was whatever the Oculnicus had seen.

It might have been a machine that had been operating for a thousand years without a living creature anywhere near it. It might have been an organism unlike anything in human biology. It might have been a civilisation whose inhabitants were watching them already, from somewhere they could not yet see.

Or it might have been something for which none of those descriptions were appropriate.

The three explorers moved away from the ship and followed the dark parallel lines toward the distant structures, while above them the strange band in the sky remained perfectly motionless.