Air moved in shallow bursts through the vents, whispering like voices. The studio sat half-lit by a battered old lamp Soahn had found in a derelict train carriage, a scatter of cables and cracked screens humming their low, constant lullaby. Kairo’s last mix still haunted the air in a fractured loop that hadn’t quite died.
Rayne adjusted the gain on the nearest deck. Static folded over itself in slow waves, the underground’s mechanical respiration steady beneath it. He logged the baseline frequencies and mapped the sound of the tunnels, letting it stretch out, waiting for equilibrium in the noise. But something lingered within the sound—a strange pulse at the edge of hearing. Higher, lighter. Out of key.
He recalibrated his sensors, narrowing the band. The tone remained, but it was too deliberate to be interference, too… alive to be machine.
Rayne paused, listening closer. The air seemed to tremble around the sound. He remained still for a long moment, tracing the faint rhythm in the air—an echo looping just beyond comprehension. The others would call it distortion, but it didn’t feel random. It felt aimed. He reached for a portable recorder, its worn casing rough against his palm, and marked the frequency on his internal log.
He rose, slipping the hood of his coat up over his head, the magenta glow from his barcode collar catching on the fabric’s inner lining and painting his periphery in familiar colour.
If the sound wanted to be found, he would follow it.
Every few metres, the signal shifted, climbing and dropping like a heartbeat trying to find its rhythm. Rayne adjusted his internal sensors, calibrating to the sound’s fragile pitch. The data scrolled across his display in fragmented waveforms—thin, human-looking shapes made of noise and nothing.
He crouched by a junction, wires spilling from an open panel, and held the recorder near the vents. The air vibrated, soft but insistent, as though the frequency had shape. If he filtered the input, he could narrow the range. The hum thickened in response. A harmonic formed inside the distortion, distant and almost melodic.
Not interference. Not feedback. Something with intent.
Rayne reached for the deck controls and replayed the sample. The tone wavered, then bent upward at the end like a question.
“Too deliberate,” he murmured, his own words sounding foreign in the deep quiet.
He isolated the file, looping it once more. The modulation didn’t repeat perfectly—it reacted, as if the sound itself was listening.
He tilted his head. The next pulse rose, closer this time, slipping between frequencies until it almost resembled breath.
Rayne straightened, the recorder still running. The sound slipped away down the corridor like it had somewhere to be. He followed, careful and silent, his boots whispering against concrete slick with condensation. The further he moved from the studio, the colder the air grew, filled with the thrum of sleeping machinery.
He adjusted the frequency again and the pitch responded—higher now, almost eager. Every few steps it drifted ahead, always just out of reach. He logged the signal strength, though he already knew it wasn’t behaving like data. It moved like thought.
The others were long out of earshot. The Ghost Lines swallowed their faint warmth whole.
Rayne kept going.
The tunnels narrowed as he descended. Pipes veined along the ceiling, sweating condensation that fell in slow, rhythmic drips. Each drop landed in a shallow puddle and sent small ripples through the reflected light, distortion within distortion. Rayne’s steps echoed in soft counterpoint, perfectly timed, until the signal shifted again—one pitch higher, as though answering.
He paused and tilted his head.
The sound wasn’t constant anymore. It now came in fragments—three short tones, one long. The pattern definitely wasn’t random. It was calling.
He reached the lower level and crouched beside a junction box half-swallowed by rust. An old London Underground insignia was still faintly visible beneath the grime: a circle split by a single vertical line. He brushed a thumb across it, leaving a clean streak through dust. Echoes of a past he did not know.
For a second, the signal flared, sharp enough to sting.
Rayne steadied his breathing, recalibrating. His diagnostic display flickered to life across his vision, mapping the sound’s trajectory. It pointed deeper, through a narrow maintenance corridor long since sealed by time and decay.
Only once did he hesitate, glancing back up the tunnel, in the direction of their makeshift recording studio far behind him. Then he stepped forward into the dark.
The tone followed, or maybe it led. Either way, he matched its rhythm, step for step.
The corridor narrowed until he had to turn sideways to pass. The signal thinned with distance, a single thread of sound running through static. When it returned, the tone had changed—warmer, more shaped.
He slowed and listened.
There, between the layers of noise: his own cadence. The rhythm of how he spoke. How he sang.
But how was that possible?
Rayne’s throat tightened. The signal wasn’t ahead of him anymore.
It was answering from inside.
He reached the end of the corridor where the air grew colder, thinner, almost brittle. A cracked relay sat half-buried in the wall, its screen wavering through grime. The NuYu logo ghosted across it every few seconds, dissolving and reforming like a phantom.
Rayne brushed the dust away with the back of his sleeve. A cable dangled loose, sparking once in protest.
He set the recorder down and replayed the signal, but the sound that came back wasn’t like static anymore.
It was a voice.
His voice.
Faint, blurred around the edges, but his tone precisely—those same vowels, that same controlled lilt he’d been trained to use on stage all those years ago. The recording carried the shape of memory: a singer caught inside the machine.
“I’ll call to you quietly,
Even if it’s the last time—”
The line rose from the relay’s speaker and filled the corridor. Every sensor within Rayne spiked and for a moment he couldn’t move. Then, gently, almost reverently, he replayed it. The voice repeated the same phrase. He let it run.
“If only in dreams
May we meet again.”
He drew a slow breath, his internal fans whirring softly. The loop had no metadata, no timestamp, no source file listed—just a string of characters: R0_19.
The system didn’t know where it came from. Neither did he.
Another line broke through, softer, almost tender:
“Memory covers me,
and I disappear.”
His vocal processors glitched once, a tightening that wasn’t mechanical but buried somewhere deeper — an echo of a human reflex his system still tried to mimic. He grazed his fingertips across the surface of the relay as though touch might confirm reality, and his diagnostics flashed a quick warning: unlogged process detected, internal uplink interference.
But he didn’t disconnect, because beneath the distortion, he heard something new: a second layer, vague but synchronised with the first. The harmonics matched his current vocal pattern exactly.
The voice wasn’t just playing.
It was listening.
Rayne stared at the waveform pattern dancing across the relay’s broken screen. Each twist answered the beat of his breathing with perfect precision, as though the signal had mapped him, not the other way around.
He should have logged the anomaly. Should have shut the system down and returned to the higher levels. But he couldn’t move.
Instead, he leaned closer. “Who sent you?”
The sound stuttered, then returned a faint harmonic echo. His own voice pitched lower, blurred by static.
You did.
For a second he thought he’d imagined it. But the waveform shifted again, synching with his collar band. Magenta spilled out of his hood until it was the only colour he could see.
If the signal could answer, then it could remember.
And if it remembered, maybe it would help him finally recall the things that hovered at the edge of his systems — fragments he couldn’t grasp but somehow knew were there.
He rerouted the connection through his internal console, bypassing the relay entirely. The frequency persisted, steady and unbroken, directly through his own interface, no longer an external thing like he’d first thought, but something that was nested inside his own architecture.
Rayne overlaid system diagnostics across his vision. The data loop was small, recursive, feeding back on itself through a sub-channel marked sleepmode/echo.
He had never created that file.
He ran a trace anyway, and the log returned fragments of language, rhythmic but incomplete:
echo_ID: 0000-R
source: unknown
status: active
“That’s not possible,” he whispered.
The signal rose in answer, a pitch too close to breath that threaded through his core audio processors, brushing every sensor as it passed. Each tone carried residual warmth, something his systems didn’t register as heat but still recognised as… human-like.
He ran the file again, the lines unfolding in perfect synchrony with his own internal fans.
‘In the stillness,
I search for your voice.’
The waveform shimmered in the air, and Rayne realised his lips were moving, soundless but matching every word.
‘a small breath
in frozen time.’
This wasn’t simply playback. This was a response.
He ran a secondary test, isolating the origin point. The coordinates resolved against his chest cavity, not the relay.
The voice had never come from the tunnels. It had been transmitting from him all along.
For a moment he just listened, the sound moving through him like memory, like light through glass. It wasn’t intrusion or corruption; it was remembrance. The system called it feedback, but it felt closer to heartbeat.
He lifted a hand to his chest, half-expecting to feel vibration beneath the casing. Nothing—only stillness. He wasn’t sure why he expected anything else.
Yet the signal kept time with a rhythm he knew was there, or had once been.
Rayne reset the recorder, his fingers moving on instinct. The tunnel had gone still again, sound folding inward. Only the hum from his internal systems remained, soft and steady, a metronome in the dark.
He pressed record.
The phantom voice rose immediately, faint and uncertain. Rayne adjusted his mic input, matching tone and pitch until their frequencies aligned. Then, without conscious thought, he began to sing.
The harmonics merged on the first line.
We sleep.
He layered his voice over the echo, letting the feedback build and soften until the distinction between them blurred.
We stay.
The sound filled the corridor, bright and fragile. After so many years powered down, his voice wasn’t perfectly human-sounding anymore, not the way NuYu had programmed it to sound originally, and neither was the one answering him. But together they created something whole.
We fade.
The old relay glowed under his hand. He could feel its failing circuits struggling to hold the resonance, the way his own processors strained to keep up.
But he didn’t stop.
“Even if the signal dies,” he whispered, “our song goes on.”
The phantom voice repeated it, slower this time, carrying warmth through the distortion.
The file finalised with a soft click.
He played it back once. Both voices sang in unison. No lag, no echo. Just one seamless waveform logged in his recorder.
SIGNAL_19.wav.
Rayne sat still for a long time—hours, perhaps days—holding onto the file like it might break if he moved.
Eventually, he unfolded from his spot and straightened. The tunnels stayed quiet, but somewhere beneath the hush, the song kept echoing.
The climb back was longer than he thought it would be.
Light bloomed as he rose through the service shaft, the metal rungs of the ladder shivering with residual current beneath his hands. By the time he reached the upper levels, the tunnels had settled into that pre-dawn quiet where you could believe you were the only person in the universe.
Rayne expected sound when he returned to the bunker — Kairo muttering over loops, Soahn’s soft voice testing harmonics, Minjae’s laughter cutting through the hum. He pushed the door open, and the space that met him was still and silent.
Equipment lay in standby mode. A pot of tea sat on the counter, long gone cold. Cables curled across the floor like sleeping serpents. Someone had draped a crumpled blanket over the back of Soahn’s chair.
Rayne stood just inside, scanning automatically. Body heat traces lingered everywhere. They hadn’t been gone long.
He moved through the space with quiet precision, cataloguing everything that was missing. Onyx’s sidearm. Kairo’s headphones. Minjae’s portable rig. The absence wasn’t random. They’d left in a hurry.
Out of the corner of his eye, he caught movement on the console screen. The Ghost Threads interface blinked with two unread messages.
[MINJAE:] If you see this, answer.
[KAIRO:] We’re going down-line to check the old relays. Ping us if you’re alive.
Rayne stared at the screen. The messages looped once, text dimming and returning. He hadn’t known that the human equivalent of lag could feel like this.
He hesitated, fingers hovering above the input field. Then he typed:
[RAYNE:] Returned. All signals intact.
The cursor blinked. No reply.
Rayne set the recorder down on a nearby table and pressed play. The soft lull of Signal 19 filled the room—two voices, his and not-his, rolling over each other like waves.
He settled into the chair nearest the soundboard, pushing his hood back. The bunker felt smaller somehow, full of echoes that weren’t his.
For the first time, he understood what absence sounded like.
The door thumped open behind him.
Kairo burst through first like a tornado, hair askew, jacket half-zipped, voice already rising. “You absolute phantom!”
Minjae followed on his heels, breathless, carrying his rig under one arm. “We thought you’d been scooped by NuYu. Or melted into the walls. Both were on the table.”
Rayne turned in his chair, calm as ever. “I was recording.”
“For three days?” Soahn said. It was the closest to shouting Rayne had ever heard him. His neural filaments pulsed from purple to blue as he stepped forward, scanning Rayne from head to toe like he needed proof of life. “You didn’t answer any of our pings.”
Onyx came in last, slower, eyes narrowed but not angry — the kind of controlled expression that only existed to keep emotion in check. “Next time,” he said evenly, “you tell someone before you vanish. We don’t need more ghosts in The Ghost Lines.”
The room fell quiet for a moment, filled only by the buzz of the deck still looping Signal 19.
Rayne looked at them — Minjae rubbing at the fine webbing of scars crisscrossing his hand, Kairo still trembling from adrenaline, Soahn’s neural filaments rolling from colour to colour, Onyx’s steady gaze holding his in place.
He logged everything automatically: elevated heart rates, raised cortisol markers, stress recovery indicators. All pointed to one conclusion.
Extended absence = distress response.
He filed it neatly into his internal notes, tagged with ‘Priority.’
“Understood,” he said. “If I leave again, I’ll notify the Ghost Threads.”
Kairo huffed out a laugh, half-choked on relief. “Good. Because we were about two hours away from sending Soahn in with a tracking beacon.”
Minjae dropped onto the couch, rubbing his eyes. “I was gonna say funeral playlist, but sure.”
Onyx’s tone softened by degrees. “Glad you’re back.”
Soahn gave the faintest smile. “We were worried.”
Rayne blinked, still processing the raw truth of it. “You don’t need to be.”
“We do it anyway,” Kairo said. “That’s kind of the point.”
The recorder clicked as the track reached its end; silence bloomed around them. Then the file looped, and Rayne’s voice filled the air again, layered with its phantom twin.
“Wow,” Kairo breathed. “Is that you?”
Rayne nodded.
Minjae leaned his head back against the wall, eyes half-closed. “Not bad for a missing person.”
“Can we make it an official track?” Kairo asked, sliding into his chair and tapping his console. “This needs to be heard across... well, everywhere.”
Rayne watched the light play across their faces, the static wrapping around their shapes—familiar, not echoes or memory. Real.
They think I’m family.
I am family.
He saved the note.
Then, softly, almost to himself: “Yes.”