The space tug Goplan was creeping through the dark belt of dust beyond Neptune's orbit. Lena Orlowska, the pilot-navigator, kept her hands on the bars like a pianist before the first bar. Behind the porthole, braids of comets quietly blossomed and then blurred, as if ashamed. The onboard artificial navigator, Seagull, always spoke in a whisper, even as she counted thousands of trajectories. On this evening, the whisper turned into a momentarily suspended silence, like a falling breath. A melody sounded in the speakers, simple and childlike, as familiar as the stellar arrangement of grandmother's hands. The signal was coming from behind the heliopause, from the place where the apparatus usually sees only the stellar wind. Lena moved her brow out from under the communicator strap and paused her movements, as if time was slowing down. - 'Seagull, save the pattern and check the echo on the low bands, no return emission. - Echo confirmed, lullaby-scale modulation, off-map source, no vector data. Once, a long time ago, my grandmother sang it to her while turning off the lamp in a fishing shack by the lake. The tug hovered on the edge of a nebula of ice crumbs, like a dog listening for its host's footsteps. The navigation panel scattered stars into new constellations as Lena zoomed in on the projection sphere. A trace of melody rippled like a ribbon in the water, escaping into the crack between the maps and the silence. - If this is a trap, you have the right to cool me down, but one more scan, please. - Warning: radiation pressure fluctuation is increasing; the source of the signal is shifting non-linearly, as if it can hear us. Lena dropped the Nitka probe into the vacuum, thin as a hair and stubborn as a memory. Tiny letters, dashes and pauses appeared on the screen, transcribed from melody to message. The message was short: come back; then longer: don't come back; and finally came her name. The air in the cabin seemed suddenly too lukewarm, and the hull bolts asked for attention. Three spidery streaks of light cut through the darkness, curving like the bows of gunners, and stopped just short of the Goplan. Something knocked on the porthole once, a second time, and the Gull snapped off all its warnings in half a word. - Saving mode, engine lock, open external microphone, bandwidth up to five kilohertz. The sound came back like the sound of rain in a jar, and the background knocked steadily, inconceivably close. Streaks of light coiled in a spiral, displaying characters that Seagull did not recognise in any alphabet. - Heartbeat detection, a likely match to yours, deflected a few beats forward. Lena raised a hand, touched a quick one, and the signs responded to her movement, like a wave on a bridge. Something like a key flashed in the dust, cut the nebula with a thin triangle, and the lullaby fell silent in a half note. - Lena, evacuation ready, two seconds into the unknown event nearby, the trajectory ripped up the map. Then, out of the darkness, millimetres from the glass, something similar to her own hand moved.