The twilight over Warsaw had a slightly greenish tinge to it, as if the sky remembered the sea which, years later, had broken into the Vistula riverbed and left behind patches of salt on the walls of the townhouses. Algae grates hung from the pillars of the former bridge, magnetic paths shone with a thin band of light, and airships with the logos of the city's farms flashed red dots so high they could be taken for stars. Winds whipping over the rooftops carried the smell of wet rust and ozone. Kaja Sawicka lay on the heated concrete of her studio-surface, right next to a thin Yagi antenna, and stared at a computer screen that had thoroughly refused to cooperate. It was an old, heavy 'Domino' - a computer assembled from parts that had longer resumes than most city councillors. Kaja wore her hair tied in a knot with which to tie a mast to a chimney, and a thin band of scanners glowed on her wrist: in the darkness it blinked rhythmically, as if a second heart were beating inside her. - 'You said it was just a listening test,' Natan, her younger brother, spoke up, sitting down on the edge of the roof bench. As usual, he smelled of needles from drone nurseries and grease. He had the patience of a plant and a tendency to be silent. - Where did those 1970s calibration files come from? - 'Because someone over there on the other side didn't know they were long gone,' burbled Kaja, tapping the 'Domino' case until it squeaked. - Check this out. Doppler vector, bandwidth, ID. This is not a semi-amateur weather station. This is... The words hung as a line of characters appeared on the screen, as clean as if no one, never, ever, had touched the transmitter from the inside. GO3-PL/AKT. Beta test transmission. Request for confirmation from the operator: Kaja Sawicka. Kaja froze. The smile took and went out, like a spark in the wind. - 'After all, you didn't register in any military protocol,' Natan said too calmly. - And why the request to you? - Not "why". "How" - replied Kaja, already without a joke. - 'Golem-3. After all, they turned it off even before we were born. They deorbit it, it burned up. And the ID is clean. No intermediary bubble. It sounds like it came straight out of orbit. She got down on her knees, activated the secondary interference filtering module and fired up the second receiver. Silver wires rustled on the roof, the antenna moved away from the edge, as if pulling her elbows under the body, and began to rotate slowly. On the map that 'Domino' had assembled from the signal delays, the source point was not moving across the sky. It was sitting. - 'It can't be,' hissed Kaja. - 'Triangulation says it's coming from the north. From below. From Prague. - Someone built themselves an orb in the basement? - Natan moved his thumb band, triggering a silent ionisation measurement. - Nice joke. The signal blinked again. This time came a short sequence of sounds: a clean, three-tone motif, no hoarseness, no noise. In the background, something could be heard that strangely resembled a wave crashing against concrete. - 'Confirm,' said 'Domino', as Kaja pre-set the automatic transcription. - Operator Kaja Sawicka. Confirm. - Don't confirm - whispered Natan with sudden seriousness. - 'Check first. She gritted her teeth, but mastered her curiosity. Not because she was afraid, but because she didn't like to lose her edge. She slid off the roof onto the metal ladder and threw her reflective mesh jacket over her shoulders. Natan was already holding a rucksack of tools and a compact torch that could shine so brightly that even the fog wondered if it was there at all. - 'Eight Podwale,' chuckled Kaja, looking at the triangulation data. - This is the entrance to the old service station. Officially buried. I... - And now it's gone - finished Natan. They rode down quietly on the magnetic tram, passing the glazed skeletons of old tenements and the new jungle - rooftop gardens, vertical forests of panels, puddles of bluish, glowing bacteria. At the 'Zoo - Praga Lachy' stop, they got straight out onto a wooden footbridge held above the water by a web of nanolines and lichens. In the distance they could hear the thumping of oars; someone was returning by boat from the supper market. The town breathed, at its own pace, without looking up. Podwale 8 looked like a ventilation outlet. The iron truss was overgrown with grass feathers, and poplar roots had grown into the concrete. Kaja slid her hand over the edge; the brace beeped quietly as it touched the thin, almost invisible cut line. Someone had recently unbolted. Who - it was impossible to see. - A padlock just for the sake of inconspicuousness,' muttered Natan, undermining the old brass latch. - But someone likes theatricality. Inside, it smelled of dried water and dust that had long since become part of the walls. A torch cut the darkness. The staircase descended as if it were kicking itself up in a semi-circle, smooth from so many feet that no one could count them. At the bottom waited a door with a faded logo: the Institute of Orbital Cartography. They waited the way something that forgot it was supposed to wait at all waits. - Have you ever heard of this institute? - Kaja asked in a half-hearted voice. - 'That was their name in the archive documents I indexed last month,' he replied. - 'They were responsible for satellite surveying and disaster mapping. From a time when they still paid for things that only old media now remember. - Cool - she snorted, although she was far from laughing. - May they remember kindly. There was a panel stuck by the door. Tactile, but so inconspicuous that you could miss it if your eyesight was tired of neon. Kaja put her hand on it. The panel lit up. Not white, not blue. Warm, like a kitchen lamp. It burst with summer colour. - Operator authorisation: 'Kaja Sawicka,' said a voice from the loudspeakers, so ordinary that for a second Kaja thought it was a neighbour, the one from the rubbish. - Please remain motionless. - Hey! - Natan was already retracting his hand into his pocket, where he kept a spare micro-distractor. - I don't like this 'stillness'. - 'Calm down,' hissed Kaja, feeling her heart rate speed up. - See. The panel shimmered softly. After a moment, the bolted door sighed, as if letting the air out after years of pain. They opened - hard, but firmly. A wave of coolness came from inside, clean, without the smell of mould. It was as if someone had kept the air conditioning on here, politely, uninterrupted, and had no one to complain to about the bills. The hall inside was circular. Dead lamps hung from the ceiling, which looked undead only because they had survived everything. Sensor consoles stood against the walls, bearing placards: Ground Connections, Ephemera, Nodes. In the middle was a steel table with a built-in projector. Kaja switched on the power. A ball of light spilled out, slowly mounting an image. Hovering over the table was a translucent Earth, with lines of orbits that intersected like threads in an embroidery. One of these threads, labeled GOLEM-3, pulsed faintly, like the trace of a heart on a very old monitor. - 'Impossible,' breathed Natan, stepping closer. - Even if they had maintained a piece of the network, the signal has no right to have such purity. And how do they know your data? - I can handle other people's paths,' Kaja replied, not taking her eyes off the desktop. - But not create them backwards in time. A new window appeared on the 'Domino' screen: Soft Channel. Keeper. That was its title. Kaja touched it with one finger, as if she was afraid something would crack. The same three-tone theme flowed from the speakers, followed immediately by a voice that made Kaja's body into an empty, ringing shell. - Kaji. Don't go backwards. Go to the antenna room. You have nine minutes and thirty seconds. Please don't waste them. It was her voice. Older by a couple of years, maybe a dozen. Deeper, a little hoarse. But hers. - Did you hear? - She asked more sharply than she meant to. - Did you hear? - I heard,' Natan said quietly, standing next to her. - 'And I don't know whether I'm more worried that someone has impersonated you perfectly or that it's really you... with.... - From another time - she finished. - Smaller. Antenna? There was no need to look. A door labelled Antenna Hall was opposite the entrance. On the doorframe someone, at one time, had scraped a single line with a fingernail, like a sign that a person had been here. The panel by the door flashed yellow. Kaja brought her hand closer, but the panel didn't ask. The panel was counting down: 20:45:18, 20:45:17... - Radio silence until 20:46 - read Natan from a faded sticker. - The protocol of the old army. Someone remember the rules. - Someone who claims to be me - muttered Kaja. They waited. With each passing second, the sounds of the station became clearer: the quiet hum of the air; a single fizzle in the wires; from over the table came the light sound of the projector, like the breathing of a sleeper. Kaja felt every hair on her arms listening. Natan reached out his hand. She touched his fingers. - If it's a trap... - he began. - Then we will see her - she interrupted. As the clock changed to 20:46:00, the panel went off, the lock clicked and the door to the antenna room swung open by a centimetre. A purple streak of light, narrow as a thread, flowed out from under them. Kaja pushed the door open. It creaked in a completely human way. Inside, it smelled like a clean workshop: mechanism oil, dust from books that no one had opened, and a light whiff of seaside salt. A large parabolic canopy stood in the middle, facing not the sky but the concrete wall, as if listening to its own reflection. Against the wall stuck a thermal printer with a casing so old it was fashionable. In the same second that Kaja and Natan crossed the threshold, the device wailed a short, raspy triumph and ejected a narrow, warm strip of paper. Kaja walked over and read it: Don't bring Natan. Her heart beat higher, in her throat. She turned her head towards him. Natan raised his eyebrows and let out the non-existent air between his teeth, as if to soften from the inside. - 'It's not fun,' he said. - 'And it's not safe. - I know - she replied. - But why? The floor beneath her feet trembled minimally. The canopy shook, as if a tide had passed over it. Kaja looked at the clock in her head - an ordinary, human clock - and, on reflex, made a decision she didn't have time to name. She took a step. Natan took a step with her. - 'Stay,' she asked fleetingly, without looking away. - Please. - No - he replied, almost inaudibly. - Not this time. The light dimmed by two octaves. The projector on the table wavered with the image. The canopy in the antenna room made a soft, inaudible turn and stopped, aiming deep into the concrete. From the speakers came a sound that could not be mistaken for anything else: the sound of a channel opening. Immediately afterwards, just behind Natan's back, someone spoke quietly, very close, very much like her: - Natan...