The artificial island of Jantar looked at dawn like a beacon in the middle of a steel sea. From the mainland, from Hel, all that could be seen was a thin black line creeping upwards - the support cable of the orbital lift, so smooth that it seemed like a spiral of smoke frozen in the sky. Ada Koss liked to sit on the railing of the service platform and listen to what no one else could hear. There was music in the cable. - Can you hear it again? - Iwo Szarek pressed his hand against the railing beside her, as if trying to feel the heartbeat of the steel giant. - 'It's not the echo of the pods this time,' muttered Ada. She had her dad's old oversize headphones on her ears and a homemade resonator with a piezo sensor soldered on her wrist. The LED flashed green in a rhythm that didn't stick to any timetable. Salt from the fog settled on their eyelashes. Cleaning drones flitted across the platform like silverfish. From afar came the sound of the harbour sirens and the quiet buzzing of the generators, but above it all - above, below and across - something else trembled. It wasn't in the official logs. Ada checked - yes, she checked more often than she should have. - 'Record it,' said Iwo. - I'll run the analysis. If it's from the transmission from GEO, it should match the known harmonics. - It doesn't match. - Ada smiled crookedly. - And that's why I like it. After a quarter of an hour they were already sitting in the small school laboratory on level B-3, between the tool cabinets and the anti-vibration mats. Coloured diagrams were flickering on the wall, like an aurora made up of pixels. Iwo, who had patience with code and an unusual sense of humour, pulled a series of data through his own filter. - 'Okay,' he said, leaning back in his chair. - 'Either your sensor was swimming in the aquarium yesterday, or... someone is just playing prime numbers with us. Ada leaned over until her forehead almost touched the monitor. - Breaks: 2-3-5-7-11 and back again. And again. As if... as if someone was pinging but had no hands. - Not a normal ping from the pods. Question: from where? Somewhere behind the wall a trolley passed by. A few grains of rust fell from the ceiling. Ada felt the familiar, dangerous warmth return under her sternum: a curiosity that made her father wrinkle his brow and say: "Not everything that twitches is for you". - Service Platform 12 - Iwo tapped on the keyboard. - It has the most sensitive transducers for up to four kilometres. But you know they shut it down after last month. We have a ban. - You mean: we don't have permission. - Ada fixed her gaze on him, as if wondering if he had already crossed the line where he usually turns back. - It's not the same thing. Iwo sighed. He knew that if they were already following a rhythm, they wouldn't be stopped by yellow tape and two red triangles with the word 'SERVICE' written on them. Besides, he liked the feeling almost as much as she did. The tunnel to P-12 smelled of grease and salt water. The walls, clad in composite panels, shimmered with traces of old repairs. On the way they passed three active cameras. Two were blinded by Iwa's hologram, which tossed a tranquil image of an identical corridor without people into their lenses. The third they didn't have to fear - someone had suspended it on test mode. - How much time do we have before the guard on the B-ring changes? - whispered Ada. - Twenty-seven minutes. - Iwo glanced at his watch. - Unless Boat Zero orders an emergency test. - Stop. - Ada didn't like it when he pronounced the name of the central control room like an incantation. The ladder at the end of the tunnel was as cold as ice. Ada's fingers were sticky on the rungs, even though she was wearing gloves. As they slid out onto Platform 12, the wind greeted them. The horizon cut a white line of clouds. The sea churned far below them, and the support rope - thicker than anyone suffering from a fear of heights would like to imagine - soared straight up, straighter than thought, into infinity. - See. - Ada pointed to a diagnostic panel shielded by a transparent flap. Status loop: normally green, now - every few seconds - a yellow zigzag was popping up. - This is it. - Iwo pulled his glasses from his temples, through which he usually viewed the world with a layer of commentary. - I'll plug in. Ada put the resonator to the truss, supported herself with her back against the pole and closed her eyes. The tremor of the cable passed through the metal, through her shoulder blades, straight up her spine. She counted the pauses in her mind. Two. Three. Five. Seven. Eleven. It started slowly, then sped up, like the shivers that run through your skin when you know something important is about to happen. - Ada. - Iwa's voice sounded different than usual. Quieter. - I have something. I've been bounced into a layer we shouldn't have access to. Someone is trying to establish a session from a registry that is not listed. Name: 'Sigma'. - You're kidding. - I'd rather. The wind tugged at their jackets. A drone drove over the platform, screeching a tune as if nothing was happening. Ada glanced up. The sky was the colour of fresh steel. Somewhere out there, thousands of kilometres above them, a geostationary node was orbiting - a station to which capsules attached themselves like beads to a necklace. Ada had never been higher than the E-ring, where she could still smell the salt and hear the seagulls. But she knew the maps by heart. - 'If it's from above,' she said, 'then we can see the course of the capsule. It must be written in the schedule. - It isn't. - Iwo shook his head. His hair danced in the wind. - And that's the most worrying thing. A tiny spark flashed on the horizon. A tiny point that under normal circumstances they would have taken for a glint of a plane. But this point was not disappearing. It was growing. The lift line trembled harder, as if someone had pulled it from the sky. - Oh my... - Iwo swallowed his saliva. - It's a capsule. There's no transponder. - That's impossible. - And yet. The signalling on the panel jumped up. It jumped from green to orange, then back again. Someone, somewhere, was trying to match the schematics to reality. Someone else - or something - was playing by different rules. The capsule emerged like a shadow. First they saw a twisted flash, then a shape: a cylinder with a rounded prow, wrapped in a layer of old paint. It was smaller than standard, with the remnants of a logo on the front that might once have been a university crest or the mark of a private corporation; now it was just a fragment of a letter and a radius-cut circle. - Can he see us? - whispered Iwo. - 'We can't be the only ones on the platform he can 'see'.' - Ada felt her stomach squeeze. - But we are the closest. The braking of the capsule was almost silent. The magnetic couplers played in a low, throaty tone, like the sound of a great flute, and the cabin settled down on the P-12 guides, centred as if it were her home platform. Everything continued without alarms, without red lights, without running. It was as if the system had decided that this was the way it was supposed to be. - Maybe we should... - Iwo interrupted. - Run away? - Ada smiled briefly, but her eyes were serious. - When was the last time something asked us by prime numbers not to run away? A new frame flashed on the panel: SESSION: LOOKING. STATUS: UNKNOWN. Below that, at the very bottom, tiny text where it was hard not to feel a twinkle: GUEST: SIGMA. A narrow slit, like the smile of a knife, spread out from the side of the capsule. It blew out cool air with the smell of ozone and cold wires. A plume of steam flowed from inside. Ada and Iwo reflexively took half a step back. The rope above their heads trembled once, briefly. Twice. Three. Five. Seven. Eleven. - This... this is the sequence of the entrance,' said Iwo, in a trembling voice. - He opens the sleeve. The locks on the capsule rustled, as if someone was rearranging the cards in a very old deck. And then - knock. Knock. Knock-knock-knock. A sound that the dead machine had no right to make reverberated through the metal cage of the platform. For a second Ada was sure it was just an echo in her head. But Iwo looked at her and she knew he had heard the same thing. - Ada... The door of the capsule vibrated and opened a hand's width apart. A snake of light spilled out from between the two halves, like a thread of fluorescent water. In that gap something flicked, thin as a hair, quick as a breath. The panel flicked. The wind quieted, as if waiting. Ada tightened her fingers on the railing. She took a breath in. A quiet whisper of mechanisms came from inside the capsule, and then the light spread wider, across their faces, across the floor, across the wind. And before they had time to step back or take a step forward, something moved inside.