Station Horizon orbited slowly over the black ice of a distant dwarf planet. In the window of the observatory, instead of the sun, there was only a grid of stars - sharp dots on an inkblot background, not flickering, too pure, as if someone had hammered them into the glass from a ruler. Inside was twilight, unsealed only by a touch of greenish glow from the console. Nela pressed her forehead against the cooled viewfinder. Her hair floated around her temples like a bright, gravity-free flame. She wandered her thumb over the trackball, sharpening the bandwidth, and the radio was deafeningly silent, as if the cosmos was muffling its own whisper. - 'Two more clicks to the right and you'll have perfect quantum noise,' muttered Iwo, entering the cabin from the corridor with a backpack of tools strapped to his shoulder. - You might even hear the universe snoring. - 'The universe doesn't snore,' Nela replied reflexively, although the corner of her mouth twitched in a smile. - But there is something trembling in it today. There were the youngest people here. Two seventeen-year-olds thrown into the fringes of the system as part of an apprenticeship programme, between adults who moved around the Horizon with such ease as if they had been born in microgravity. For Nela, the black silence behind the portholes was both an ocean and a well. The thought that thousands of kilometres below them lay dormant ice cones and rocks older than the Earth's memory made the skin on the back of her neck chill. And nice. - 'Orion, confirm the calibration of the radio telescope,' she called out, without taking her eyes off the screen. - 'Confirm: matrix normal, thermal noise stable, reference transmitter at nominal level,' replied the station's AI calmly, in a voice modulated to sound like a grouse purring in the high forest. That was how the mission manager had once set it up for himself. Nela was unfamiliar with the bird, but it sounded pleasant. Iwo attached his rucksack to the railing and bounced up to hover above Nela upside down. - Did you know that the kitchen had run out of real coffee packets? The only ones left are the ... flavoured ones. Chocolate with peppermints. Who normally drinks chocolate with peppermints in space? - One who is cold," she replied. - Quiet now. Something trembled on the screen. At first it seemed a mere modulation of noise, a tiny fluctuation like the millions that swept through the apparatus. Nela changed the bandwidth. The curve drew out again, this time more clearly. The teeth, the inflections, the gaps.... She had the impression that she was looking at a sentence fragment written in an alphabet she had not yet learned. - Orion, log. D-band thirty-two, width two megahertz. Can you see it? - Analysis in progress... - AI murmured a little lower. - I'm detecting repetition. The differences in amplitudes are arranged in a sequence of prime numbers. This does not match known phenomena in this region. Directional source. Azimuth two hundred and sixty-eight, elevation minus three. Iwo stopped twiddling his thumbs. He looked at the chart and at Nela, quickly and carefully, as when something was finally catching him for real. - Anyone broadcasting this? - 'Something,' Nela corrected, more to herself than to him. She didn't believe in any 'someone' roaming around Sedna. The area was empty, or at least empty in human terms. - Check the internal sources. Maybe we have a reflection somewhere, an intermodulation, whatever. - There - Iwo pinned down the diagnostic panel. - Reference transmitter clear. Receivers normal. North antenna ... moment. Beacon in hangar C just woke up. Nela moved away from the console as if someone had electrocuted her. - Beacon of what? - The old dock. The one that had been disconnected for years. Who turned it on? - Nobody. They're all asleep or on ag (active gravity) in the rotating module. - Nela fled with her eyes to the porthole, as if the answer would come from outside. The blackness was indifferent. - Orion? - I am reading a sync pulse from outside. The beacon responded as the signal was in the correct format. - What format? - Iwo finally sounded as serious as Nela felt. - Exactly as used by... - SI fell silent for a fraction of a second. - ...Kruk-12 probe. Nela knew the name. Pictures of the Raven hung in the school corridors alongside the first shuttles and pictures of ancient sails. It was a probe sent straight into the darkness, when it was not yet known what Maupertuis was doing with orbits far beyond Neptune. It was supposed to disappear into the statistical noise. She disappeared. Two decades ago, the last ai telemetry report flashed only a very faint, gruesomely distorted ping, after which it was declared dead. - Raven is... in the vicinity? - Nela asked slowly. - 'The signal trajectory indicates an object drifting in the plane of the Horizon's orbits,' replied Orion. - Relative velocity extremely low. Distance approximately three hundred metres. Probably a fragment of a former shield or instrument module. I suggest a visual observation. - 'Three hundred metres,' repeated Iwo, as if savouring the word. - That's less than the length of the entire dock. I'll send a spider. 'The spider' was a small vision drone with micro-drones. Nela watched as the slender shape detached itself from the cargo rail and slipped into the blackness through the service airlock. On the screen appeared a division of stars split by a faint cone of light. The darkness did not like the light from the spider. It absorbed it instantly, leaving only a sheen of specks that looked like dust suspended in the air. Then the cone touched something bigger. Edges etched themselves into the frame. Outlines. Inscriptions gouged out by micro-impacts, but still legible. K R U K - 1 2. - 'It's impossible,' said Iwo in a whisper, as if he feared someone was eavesdropping through the vacuum. - It's impossible, and yet here he is. Nela felt her stomach do a flip, despite the lack of weight. The probe looked like something someone had held underwater for a very long time and released at the wrong moment. Rough, covered in black ice, rippled with tides of dust. Yet the shape of the instruments was unmistakable. Patches of heat sinks folded like wings. - Orion, why did the beacon speak up? The raven should not know our code. - 'It was not the Horizon that answered the Raven, but the Raven to the Horizon,' replied the AI, and for the first time something like curiosity trembled in its tone. - 'It received a calibration signal from you and transformed it, using a a scheme very similar to ours, albeit with a phase variation that we don't use. He then sent it back. This acted as a key. - Is he eavesdropping on us? - Iwo reached for the back of his chair, although there were no armchairs to lean on. A habitual gesture, from Earth, left him with his hand suspended in the air. - He is eavesdropping on us,' slipped out Nela. For a moment, all three of them - two humans and one programme - stared at the silent shape in the spider light. Words swirled around Nela's head, useless and unnecessary: old ballads about lighthouses, her grandfather's stories about the Isle of Sobieszewo, where the fog could eat up the whole morning. She felt she had something of the same category in front of her here: some kind of thing-not-things that connect places and times, if you just look long enough. - 'Protocol says that in a situation like this you have to report to command, lock out all automatics and wait,' Iwo reminded her, but it sounded like a repeat of a lesson, not a decision. - There is no time to wait here,' said Nela. - 'See the rubbish forecast. In six hours we enter the cometary dust nebula. If we don't catch the Raven now, it will fly away the way it came. Or it will disintegrate into shavings. Iwo sighed, ran a hand through his short hair, which floated above his head like a soft cloud. - And Mira? - That name meant as much as 'conscience'. Shift manager. She was in the rotating module now, testing artificial gravity with a geologist. - 'She's asleep,' Nela replied. - 'Internal communications are delayed because they switched routing. 'Orion, if we go, will you guide us? - 'My job is to support the crew's operations within security,' said the AI after a pause. - 'There is no contraindication registered for a short external mission provided we stay within range of the manipulator and rope. The other crew member must remain at the airlock. - 'The other will not stay,' Nela and Iwo said simultaneously, and then both giggled nervously. Laughter in the vacuum sounded like nothing: tin in the ducts, steam in the helmets. - Good. - Iwo nodded. - Fifteen minutes to get ready. We take ropes and two arrow harpoons. The spider stays as a marker. We don't touch the surface if something reacts on it. - We don't touch anything without each other's permission," added Nela. They stopped talking and started acting. Movement in microgravity was like dancing underwater, but without resistance. Nela was getting dressed and her fingers were slightly trembling - not from fear, from over-attention. Layer after layer of wetsuit becomes part of the body. Seals to click. Joints to click. Fastening the rifts between who you are and who you need to be when you go into space. The airlock hissed, but not like in the old movies. In fact, almost silently, as if the station had stretched its back after sitting for a long time. The outer door slid open and emptiness immediately flooded the interior - not cold or dark, because that was already there, but the absence of everything people were used to: smells, sounds, tiny background vibrations. Nela could only feel her own breathing and pulse, and in her headphones, quiet as the cold rain outside the window, Oranje's signal. An altered wave from Raven. - Rope secured,' reported Iwo, his voice slightly metallic. - Harpoon one ready. Two ready. - 'Let's go,' Nela said and pushed herself gently out of the airlock frame, as if from the curb of a swimming pool. She knew the move. She had done it hundreds of times on the simulators. Only now, instead of blanked-out screens and artificial blackness, she was gliding towards the real, endless night with every push she made. The spider blinked a pinpoint light, like a skylight at the end of a forest path. It was guiding them. Nela and Iwo moved along the rope like two climbers on an icefall, except that the icefall here had no top or bottom. They passed the smooth panels of the station, hooked up by sparse strands of cable, and then all that was left was space. The Raven grew slowly from a tiny shape to something that could be described with eyes, not a number of pixels. On its surface, the ice was not white, but black, as if it had risen from the shadows. Specks of dust enveloped it like a sandstorm stopped in mid-step, yet some edges still shone with metal, too clean to be old. - Can you see the scratches? - Iwo pointed to one of the heat sink plates. - 'They're not micro-impacts. They're parallel. It's like someone dragged something over it. - Or as if something is sliding on it,' Nela said. - Orion, a spectroscopic approximation of the surface. What composition? - I detect water ice, a hard mixture of volatile compounds, metallic impurities. Nothing of concern. However, one panel shows an emission pattern in a narrow infrared band. Analysis... is a modulation similar to the signal you recorded earlier. - Is he glowing? - Iwo squinted, although it made no sense in his helmet. Nela saw what he was talking about: bright dots were slowly moving on one of the panels, barely visible. They formed a line for a second, then an arc, then something that looked like the spiral arm of a galaxy drawn by a child. It wasn't a sign she understood. It was a rhythm. The light went out and came on at intervals that Nela reflexively began to count: two, three, five, seven. Numbers she had been hearing in a hum since the morning. - 'Nela,' spoke up Iwo quietly. - 'If we get any closer, I'll hook the harpoon to that beam over there. We don't go to the surface. We'll just attach it and slowly pull it into the dock. - Good. - Nela swallowed her saliva. - Slowly. They approached, gently correcting trajectories with short blows of the microdisks. The harpoon flew through the weightlessness, unfurled the rope like a silver spider and grabbed the beam at the edge of the Raven, clenching with a clever tooth. The rope puffed out for a second, then tightened with a straight line between them and something that had been nothingness for too long to remember what movement was on its own. At the same instant, the signal in the headphones changed tone. Orion spoke up quickly: - Warning: modulation is accelerating. I am registering a coupling with the communication system of your suits. I recommend disconnecting the auxiliary channel. - 'Disconnect,' Nela said. For a split second, there was a silence so perfect in her helmet that she felt her own muscles creak in her shoulders. Then the breathing and Iwa's voice returned again. - 'We're at beam two. Can you hear me? - I can hear you. - As she spoke, she looked. She looked at the edge of the panel, where the ice was arranged in a texture reminiscent of tree bark. She looked at what was beginning to pulsate under the ice like a faint blue heart - one, two, three, five.... - Nela - Iwo drew in a breath. - This was not how it was supposed to be. The raven twitched. Minimally. The movement was so subtle that it could be taken for an illusion. Yet the rope on their belts trembled at the same moment. The spider noted the shift. Orion said very calmly: - I was recording micro-rotations. The object is vectoring itself. Nela, Iwo, please keep your distance. - 'Look at panel three,' said Nela so quietly that she herself could barely hear her voice. On panel three, under a thin layer of black ice, like under a frozen river, something was moving. It was not something that could be described as a hand or a mechanism. Rather, it was a streak of darker shadow that traced the point of the spider, paused beneath it and then, anticipating their own intentions, moved perfectly in line with Nela's helmet - as if looking directly at her. - Orion... - she began, but the AI entered her word in a voice already devoid of purring gentleness. - Immediate evacuation. Airlock B prepared. Nela, your heart rate is increasing. Iwo, you have a hand tremor. You both turn back. - One more second - she whispered. - I'm almost there... I'll see. She didn't want to touch. Yet she held out her hand the way one holds out one's hand towards the glass behind which a deer runs. Nothing more. A gesture without consequence. She froze. The panel moved again. This time indiscriminately. Not like a mirror reflecting, but like an eyelid twitching as she decided to open it. The edge of the ice, hitherto smooth, split in a thin black line. A light shone in that crack, different from before: not a sine, not numbers, just a short, impatient flicker, like a signal from a torch. One. Two. Two shorter. Three. A static buzzed in the headphones. And then they heard a voice. Not Orion's. Not Mira's. A voice that sounded like Nela's, only shifted by half a tone and pulled inwards, like an echo in a closed corridor. - Nela... don't touch.