The twenty-third circuit of the Mirra station around Enceladus began quieter than usual. In the observation hall, the sound of the cooling pumps was barely audible, as if the entire structure was holding its breath. Behind the panoramic glass, Saturn's moon looked like a glowing ball of icing sugar, and its geysers splashed towards the vacuum with silvery plumes. Squeezed between the console and the window, Lena Korczak held a mug of tea with her hands to keep the heat from escaping her fingers. Across from her orbited Saturn, majestic, with rings like the thinly outlined curves of a pencil. - 'Daria, replay the last eight hours of Padma Seven,' she said, not taking her eyes off the patches of light on the hull floating in the gloom. - 'I'm sending,' replied the station's artificial intelligence, in a voice as calm and colourless as the old geography lecturer Lena still remembered from Earth. Graphs lit up on the screen: temperatures, minute variations in the magnetic field, background noise. Lena knew these curves better than the distribution of her own freckles. She was here for the fourth month, officially as a junior observer in the cryovolcanism team, unofficially as someone who could comb a notebook of sounds into strands and find a different shade of wonder in each. She loved it. She even loved the metallic smell of the filters and the dry skin from perpetual air recycling. The door slid open silently and Maks, three years older, already wearing his trainee engineer badge, with a brow full of tiny sparks of ice after a brief visit to the goods lock, rushed in. - Lena, have you seen? There was something strangely wavy in sector C3,' he chuckled without greeting, and only after a moment did he notice the mug in her hands. - And tea again. You don't sleep at night, do you? - Who would sleep with such a view - she muttered and poked him with her elbow, pushing him away from the console. - Sit down. Padma caught something. - Something? - He repeated with feigned haughtiness, but was already leaning back. Daria shifted the spectrum of noise and suddenly there was an unhurried rhythm among the tiny pixels of silence, like footsteps in a corridor in a house Lena hadn't seen for months. Her heart fluttered as she realised what she was hearing. - Don't tell me it's... - she began, and her voice trailed off. - A lullaby - whispered Maks in disbelief. - The one from mum. Daria didn't know the word 'lullaby'. She knew the frequency catalogue. Yet what filled the room when the AI translated the signal into an audible range sounded exactly like the line of melody her mother used to sing to them in Gdynia when the smell of rain came through the open windows. - 'Source: plume D-4, altitude four hundred kilometres above the equator, trajectory coincident with station orbit,' Daria reported. - Consistency analysis: eighty-nine per cent. - 'After all, it's impossible,' said Lena, and in the same poignant sentence fit her entire childhood belief that the world is explained by cause and effect. - 'Everything is impossible until you find an error in the model,' replied Maks, but his fingers also trembled over the keys. - Daria, give us the triangulation. Source relative to station. - In the process of recalculation,' AI replied. - Warning: signal disturbed by ice streams. Could be a local artefact. - An artefact that plays our language,' muttered Lena, still having a fragment of the melody in her head. Not a perfect one. As if someone knew it, but couldn't quite remember it. The line of notes was breaking off and coming back along a different path. On the screen, instead of the usual fluctuations, a pattern was outlined that didn't match anything she had seen so far. - Triangulation ready - Daria stopped sounding like a lecturer, suddenly speeding up. - The source of the signal is within two hundred metres of observation section B. Exact distance: one hundred and eighty-eight metres. Direction: vector relative to heliocentric: approaching slowly. - Approaching? - they repeated simultaneously. Lena stood up until her cup clattered against the console. The skin on the back of her neck tightened as if from the cold, although the temperature in the room was constant. - 'I'm linking the external cameras,' Maks said, his face lit up by the viewing windows from the pylons. Four angles of view, a dark void, the snow dust of geysers falling like transparent snow. - 'Zoom in,' Lena asked, pointing to a sudden flash, so tiny it could be mistaken for a disturbance. The flash, however, moved in a semicircle, like the head of a bird leaning over the sheet. The object was the size of a fist, maybe smaller. It looked like an irregular lump of crystal, dull at the edges, with something glittering deep inside, as if a tiny stream of light was trapped inside. It had no positioning lights, no response to radio pings. Yet it was moving towards them at a pace that was not random, not like ordinary space junk. - 'Daria, identification,' Maks instructed. - No match to the catalogue. Weak electrostatic charge detected. Note: rhythm of field changes consistent with the rhythm of the signal - replied AI. - So it's playing to us from the current - Lena wasn't sure if she was saying this to her brother, to Daria, or to herself attached to the glass. They shouldn't do that. The rules and regulations were clear: do not modify antenna settings or approach unverified objects without permission from the officer on duty. But the duty officer was on the other side of the station, locked in the gravity module for review, and Lena felt that if she didn't see it up close, she'd be thinking about it for the rest of the cruise, for the rest of the summer, for the rest of... everything. - 'Observation point B, now,' she said, and Maks just nodded, as if it was obvious to him too. They ran along the corridor, passing empty alcoves with spare water tanks and repair suites, until they reached a low half-dome, attached to the hull plating like a soap bubble. Above them stretched the dark shape of Saturn's rings, like half-open wings, and behind them clouds of atomised ice swirled in a slow dance. Lena pressed the tangles of her hair against her head and approached the glass. The object was already very close. It swam not so much towards them as towards the light that reflected off the surface of the station. At moments it seemed almost transparent; only the pulse inside it reminded her that it was different from a fragment of random ice. - 'Turn on the local low-power lighting,' Maks said quietly. - 'I don't want to blind him. - Attached - Daria did the right thing. - Note: external temperature of the glass drops below normal. Ice condensation on the plating. A ripple of frost dragged across the glass, as gentle as a breath. Lena looked up moved by the strange sensation that this thing was on the other side, just out of sight, like a line of gel on a glass peeler. It was absurd, because a vacuum did not carry breath and nothing could breathe just beyond the glass. Yet the trail was thickening. Instead of spreading chaotically, the frost was forming a pattern. First the shape resembled a fern sprig. Then a letter. L. - Do you see it? - mouthed Max. A second appeared: E. Then N, neat, even, as if written slowly with a finger on a frozen tram window. And then an A. LENA. The cup of tea finally fell from her hand, but the fall spread across the soft carpet quietly, almost inaudibly. In the silence that followed, all they could hear was their own hearts and the steady, persistent vibration that arranged itself into the lines of a familiar melody. - Daria? - Lena whispered. - Record everything. And... what is it? - Analysis is in progress - replied AI. - I am receiving a connection request. Format unknown. Initiating ID: LENA KORCZAK. - 'This isn't funny,' said Maks, but he sounded as if he believed the joke himself just to keep from panicking. - Daria, reject. - I can't. The request is not for a network channel. Source: direct space at the glass. Note: I register non-classical excitations in the material structure. The pattern is moving towards the S-12 service airlock. Lena reflexively looked to the side. The narrow flap of the S-12 airlock was a few metres away from the observatory, rarely used, with a red warning bar. Its control panel now took on a pale orange glow, as if on low alarm. - 'Who gave authority to this airlock? - asked Maks, already at the panel, already in engineer mode, pushing away the fear with further tasks. - No active permissions. However, the system detected a match between the pattern and the biometric matrix: 'Lena Korczak,' said Daria calmly, as if discussing the weather. - What? - Lena pulled her hand back as far as it would go. - I'm not doing anything! - Since when does your biometra work through glass? - snorted Maks, but his fingers played nervously on the screen. - A manual lock. It's supposed to be. The panel flashed. The light dimmed for a second, then returned, stronger this time. Another outline appeared on the glass. Not a letter this time, but something resembling a hand applied to the glass from the outside, five open lines of frost, slender and precise, like an imprint. Lena felt warmth in her eyes and something like a strange, wild longing she couldn't name. Her mother had insisted that she come here. She used to say that the world starts wherever you set foot. But no one said the world could knock on your door through an ice glass. - Daria, airlock status S-12 - she whispered. - Authorisation waiting mode. Unusual input sequence. Request instructions,' AI replied. - No instructions! - hissed Maks. - 'Lock it up with four triggers. And send a package to the duty officer. - Sent. 'No response,' Daria hesitated, which Lena heard for the first time since she arrived. - Note: S-12 initiates pressure equalization sequence. I can't find the initiator in the system logs. A deafening murmur came through the plating, so subtle it could have been an illusion. Lena and Maks turned simultaneously towards the narrow hatch, whose indicator turned from orange to red. At the same moment, a single, short word was outlined in the frost on the glass, right next to the word 'LENA', like an answer written with someone's cold finger: I WAITED. The lights on the sluice panel flashed once more, this time to the rhythm of a lullaby, and then the indicator started counting down.