Outside, just beyond the thick glass of the observation dome, the cosmos looked like spilled paint. A red nebula stretched along the hull of the Hummingbird like a huge, translucent sling in which someone had trapped thousands of sparks. The ship glided slowly, almost silently, yet Lena was sure she heard something. - Can you hear it? - She asked, pulling her forehead away from the glass. Olek shook his head. He was eleven years old, always carrying a notebook and an eraser, as if he could invent a new law of physics at any moment. - I can't hear anything. Just... - He furrowed his eyebrows. - Wait. Something trembled gently. At first they thought it was the pumps from the hydroponics. But this sound was different - soft, rippling, reminiscent of the melody their grandmother used to hum to them to sleep when they still lived under the dome in Krakow-Moon. A lullaby between the planets. - Amber? - Lena called back to the ship's system. - What is that sound? - 'I'm registering hull micro-vibrations at a frequency of 433 hertz,' replied the calm voice of the artificial intelligence. - External source. This is not the working noise of the installation. - So something is hitting the ship? - Olek immediately imagined a hail of small pebbles from the asteroid belt. - I'm not detecting a collision,' Amber replied. - 'It's more like a resonance. Someone or something makes the hull 'sing'. Fiszbin, their pear-sized pocket drone, emerged from under the railing. It had three propellers and a pair of curious cams. - 'I can try to trace the vibration nodes,' he buzzed cheerfully. - 'Lead the way,' Lena said, and it sounded almost like a captain's command. Not without reason. Their mother, Captain Mira, trusted them more than most adults on freighters, but she always said: "Observe first, decide later." They followed Fiszbin, who was shining a thin beam of blue light along the ring's engineering corridor. They passed the hydroponics room, where rows of green leaves floated in tiny bubbles of water, smelled of mint and heated rubber. Further on, they passed a tool store where a spanner drifted lazily in the air. The lullaby was increasing, as if someone had turned down the volume knob. - 'Here,' squealed Fiszbin, hovering by the door to hangar number two. - He shuddered the hardest. Lena touched her hand to the wall, feeling a quiet, orderly tingling under her fingers. Olek leaned into the narrow, triangular service window. From outside, something bright and hair-thin flashed against the red streaks of nebula. - Can you see? - He whispered. - Like a spider's thread. Lena clung to the glass. This 'thing' looked like a silvery fibre, almost invisible, only when it moved at the right angle did it catch the light and flare. It was attached to the plating, taut as a string. It trembled to the rhythm of a lullaby. - 'It's not ours,' she muttered. - 'We don't have any lines outside. - We don't have one,' Amber confirmed. - The catalogue of external components does not include such an object. Warning: minimum force vector applied to the hull detected. Value: 0.02 newton. Direction: towards the Red Nebula sector. - 'Mum needs to know about this,' Lena decided and pressed the intercom button. - 'Captain, we've got... a strange fibre on the plating. And a hummingbird is singing. Mira's voice sounded in the loudspeaker, dimmed by distance and a flurry of tasks. - I'm picking up. Don't touch anything. Watch and report, I'm in Engineering, the autopilot doesn't like nebulae. Amber, log every shift. - Logging," said Amber. - In addition: the vibration modulation corresponds to the rhythmic pattern... - Here the AI voice hesitated like a human. - ...Which coincides with your lullaby, Leno. - 'No kidding,' snarled Olek, but he was already jotting down notes in his notebook: long, short, short, pause. long, long, short... - It's like the telegraphic alphabet. See, it repeats itself. Le-na. O-lek. - He looked at his sister with a mixture of delight and anxiety. - How is this possible? Lena did not answer. Something squeezed her inside. It was as if the nebula knew their names. - 'External camera number six,' Amber spoke up. - 'I'm turning on the preview on the panel. The screen above the hangar door flared. They could see their ship from the outside, like a humped animal, and a fine thread stretched from bow to black. A darker corridor suddenly carved into the Red Nebula - as if someone had spread the gas sideways, leaving a passage inside. The Hummingbird, although the autopilot held its course, turned slightly, as if an invisible hand was pulling it along. - It looks like a path,' whispered Olek. - A path in the cloud. - Amber? - Lena clenched her fists. - Is it safe? - I do not note an immediate structural threat. - The AI's tone remained even, but added: - 'We are beginning to enter a region of increased particle density. I recommend exercising caution. The lullaby they had heard at the beginning now developed into a richer, more complex melody. The notes seemed to penetrate the metal and seep into them like deep breaths. The whalebone, moved by anxiety, hovered closer to Lena, as if it could defend them from something as delicate as sound. - 'Attention,' interrupted Amber. - 'External inspection airlock: activation signal. - What? - Lena jumped up. - Who activated it? - I'm analysing. Unauthorised command. The signal comes from... - a moment's pause, after which everything seemed even more unreal - ...from the thread. On the screen they saw the flaps of the inspection airlock swing outwards. No clatter could be heard in the vacuum, yet Lena imagined the groan of metal. The red limbo of the nebula was no longer a soft sling, now it resembled a throat - someone had made a passage for them and was waiting for them to go deeper. - 'I'm notifying my mum,' Olek said and was already jotting something down again, as if words could be a shield. - Fiszbin, record everything. - I'm recording - muttered the drone, and its propellers blinked faster. Then they saw a point of light move across the fibre. First a tiny one, like a skylight in the forest grass. Then bigger. It shaped itself into something more distinct - something that resembled a wing from a maple tree, only made of glass and stardust. It rotated, smooth and sure, gliding straight into the open airlock. - 'That's not a rock,' Olek stated, as if to someone other than his sister. - And it's not a probe, at least none in the catalogue. - Entering a zone of optical silence,' read Amber. - The light reflections are falling. I am activating the filters. The image dimmed, but the shape glowed with an inner radiance. Lena felt her heart begin to play the same tune as the hull. It was strange and beautiful, but also so very new that it hurt a little. Fiszbin fell silent, as if he too, the little machine, had been overwhelmed by amazement. The wingman stopped just before the service window. Gently hitting the invisible threshold of the force field, it unfolded wider, like a flower opening its petals. Lines ran across its surface, arranged in three circles one inside the other. Olek took in a breath. - 'I saw this in a book about planets,' he whispered. - Harmony... - Don't finish - Lena interrupted him. - Listen. The lullaby suddenly interrupted. In that silence, thick as cream, they heard a single thump. Then a second. There was no doubt: someone or something was knocking on the very centre of the glass from the outside, right where Lena was standing. - Lena... - Olek took a step back. - Maybe... He didn't have time to finish. The winged man moved once more. Its surface split into hairs of light that began to form a sign that no one on Hummingbird had ever seen before. At the same moment, all the lights in the corridor flicked on, and Amber's voice sounded a little quieter, as if he too had squeezed his breath: - The object refers... The light struck through the glass like a wave, stopping inches from Lena's face. The mark that was being made was just finishing being drawn.