The first thing Ha-rin noticed was the silence.
Not the mechanical quiet of a powered-down lab, not the muffled silence of city nights—but a missing sound, like a note cut out of a song she'd been hearing her whole life.
No faint hum in the walls.No gentle, teasing voice in the back of her head.
No Echo.
She stared at the blank monitor of the console, its dark screen reflecting a pale, hollow-eyed version of her.
You survived, she reminded herself.
Echo hadn't.
The thought made her throat tighten all over again.
"Ha-rin."
Jae-hyun's voice came from behind her—rough, like he'd been arguing with the world and losing.
She turned.
He was leaning on the doorframe of the observation room in his usual black shirt, sleeves rolled up, tie loosened, but there was nothing "usual" about him now. There were faint bruises along his jaw from the explosion in Loop Zero, a small cut at his temple that refused to heal neatly, and shadows under his eyes like someone had stolen his sleep.
He still looked devastatingly composed.
Except for his eyes.His eyes were on fire.
"Watchmaker wants us upstairs," he said. "They're shutting down the lower floors. Loop Zero goes into permanent lockdown tonight."
Ha-rin's fingers curled against the cold console.
"Like a grave," she murmured.
Jae-hyun's jaw clenched, but he crossed the room toward her.
"It's a machine, Ha-rin. A dangerous one. It should've been sealed a long time ago."
"It wasn't just a machine," she snapped before she could stop herself.
Their gazes collided—her eyes bright with anger, his with carefully drawn control. For a moment, neither of them spoke. The overhead emergency lights painted his cheekbones in sharp lines and threw their overlapping shadows against the wall.
She exhaled first.
"Sorry," she muttered. "I know. I just…"
She pressed a knuckle to her chest, right over her pounding heart.
"It feels wrong to leave him down here alone."
Jae-hyun's eyes followed the movement, lingering for a heartbeat too long. His voice was softer when he spoke again.
"He didn't die here." He hesitated, then stepped closer, close enough that she could see the faint tremor in his fingers. "He died saving you."
Us, she almost corrected, but the word tangled in her throat.
Because in that last blinding moment, when Echo's light had wrapped around her, she'd felt something else—a warmth sinking deeper than circuits or wires, deeper than the air around them.
Something had slipped under her skin and settled near her heartbeat.
She hadn't told anyone.
Not yet.
If I'm wrong, I'll just sound crazy.If I'm right…
Her fingers tightened on the console edge.
"Ha-rin."
Jae-hyun's voice pulled her back. He was standing just in front of her now, close enough that she had to tip her head back slightly to look at him. The distance between them was a fraction of a step—a distance that felt heavy and charged and very, very breakable.
"You're shaking," he said quietly.
She hadn't realized she was.
"I'm fine."
"That's a lie."
He said it so calmly, like he was commenting on the weather, but there was something raw in his eyes that made her chest ache.
He reached out before she could argue again.
"Give me your hand."
"What? Why—"
"Humor me."
Reluctantly, she held it out.
His fingers closed around hers, warm and steady. The contact sent a jolt through her—too familiar, too grounding. He turned her wrist gently, checking the faint bruise there from when the loop had thrown them against the metal walkway.
"You should've told Mira this still hurts," he murmured.
"It doesn't."
He pressed his thumb lightly to the bruise.
She winced.
His lips tugged in something that wasn't quite a smile.
"Liar," he said softly.
"I've had worse."
"I know." His gaze flicked up to meet hers. "That doesn't mean it has to be ignored."
Her heartbeat kicked up, loud enough she swore he could hear it.
Which was ridiculous.
Only Echo could ever hear it that clearly.
Constant… your heart rate is elevated…
The phantom memory of that digital voice brushed against her mind. For a second, the room wavered—not in a loop-glitch way, but in a grief way. Too many feelings slamming into her at once.
"I keep expecting him to comment," she blurted.
Jae-hyun's fingers tightened almost imperceptibly around her wrist.
"Echo?"
She nodded.
"Every time my heart does… whatever this is," she waved vaguely between them, "I feel like he should be teasing us."
"'Us'?" Jae-hyun echoed, one eyebrow lifting.
Heat rushed to her cheeks.
"I mean—me. Teasing me. Not—"
He didn't let her finish.
His other hand lifted, hovering near her cheek, then dropping to the console just beside her waist instead, as if he'd changed his mind mid-air.
"Ha-rin."
She forced herself to meet his eyes.
"I know Echo's gone," he said quietly. "I saw him burn out. I felt the blast. But—" his throat worked, "you're not the only one who keeps hearing him in my head."
Her breath stalled.
"You… do too?"
"Sometimes." He looked away then, jaw tensing. "Usually when you're doing something reckless."
"Reckless? I was not—"
"You tried to throw yourself between a corrupted AI and the unstable core of a time device." He flicked his gaze back to her. "That qualifies."
She opened her mouth, closed it, then muttered, "You looked worse than the explosion."
He blinked.
"How?"
"You jumped after me without a harness."
A beat passed.
His expression softened, tension melting just a little.
"Yeah," he admitted. "That was… less rational."
"Why would you—"
"Because it was you," he said simply.
The words landed like stones dropped into a lake—heavy, sinking, sending ripples through everything.
Ha-rin swallowed.
"Jae-hyun…"
His hand, still holding her wrist, slid down until their fingers laced together. It was such a small movement, but it felt like stepping over a line they'd been silently dancing around since the loops had started.
"You're allowed to be not okay," he said. "You don't have to carry Echo and Broken Ha-rin and every loop we lived on your own."
Her chest tightened at the mention of the other her—the one who hated her, who had pushed her hand through Echo's light.
"She was part of me," Ha-rin whispered. "A version that never healed. How am I supposed to just… move on?"
Jae-hyun's thumb brushed the back of her hand.
"You don't move on," he said. "You move forward. With everything you've been and everything you've lost."
She laughed weakly. "That sounds like something Echo would've said."
His gaze softened.
"Maybe he left a piece of himself in us," he said. "In our habits. In the things we say."
In our hearts, she thought.
In the way my pulse sometimes stutters like it's syncing with something invisible.
She almost told him.
The words crawled up her throat, stopped at the edge of her tongue.
Sometimes, at night, I hear him whisper your name through my heartbeat…
But the doors to the observation room slid open with a soft hiss before she could speak.
Mira appeared, cheeks still damp, eyes red but defiant.
"Are you two planning to get married down here?" she demanded, crossing her arms. "Because Appa is about three seconds away from sending security to drag you upstairs."
Ha-rin jerked back from Jae-hyun, hands flying apart as if caught doing something far more scandalous than simply holding each other.
"We were just—"
"Trembling at each other," Mira finished dryly. She sniffed. "Save it for after the debrief. They're waiting in the upper conference room."
She jerked her chin toward the hallway, then paused, really looking at them.
"Are you okay?" she asked Ha-rin.
Ha-rin swallowed.
"I… will be."
Mira's shoulders slackened a little. She stepped closer, her usual mischief dimmed but not gone.
"Echo chose you, you know," she said quietly. "Right to the end."
Ha-rin's throat burned.
"I didn't deserve—"
"Shut up," Mira said. "Deserving has nothing to do with constants."
She reached out and poked Ha-rin lightly in the forehead.
"You think too much. Come upstairs before the Board decides to turn this place into a parking lot."
Ha-rin managed a small smile.
Behind her, Jae-hyun's hand brushed the small of her back as they started toward the door—a barely-there touch that made her hyper-aware of the shape of him, the warmth of him, the fact that somehow they were here, alive, together.
For now.
The Debrief
The upper conference room felt wrong.
Too bright.Too clean.Too… normal.
Ha-rin sat at the long table between Jae-hyun and Mira, facing the semi-circle of board members and researchers. The city glittered through the floor-to-ceiling windows behind them, pretending the world was simple.
The Watchmaker stood at the front, hands folded behind his back. He looked older than she'd ever seen him—like someone had scraped out the inside of him and left only the shell.
"Loop Zero has been permanently sealed," he said. "All active projects involving Echo are suspended until further notice."
A murmur went through the room.
"What about the anomalies?" one researcher asked. "The time fractures in the city? The mirrored incidents?"
"The system reset should have neutralized all remaining distortions," another replied.
Ha-rin felt a chill.
Should have.
Her fingers tightened against her skirt under the table.
The Watchmaker's gaze flicked briefly to her and Jae-hyun.
"Officially," he said, "the experiment is over."
Ha-rin felt something in her chest flinch.
Over.
The loops.Echo.The fight with Broken Ha-rin.
Everything.
Jae-hyun's hand slid under the table, wrapping around hers.
It was a reckless gesture, but he didn't care who saw. His thumb skimmed her knuckles in a quiet promise.
Not over.Not really.
The Board moved onto logistics. Disassembling hardware. Reassigning staff. Legal coverage if any anomalies leaked to the public.
Ha-rin's mind drifted.
A faint, rhythmic sound threaded through her thoughts.
Ba-dump. Ba-dump.
Her own pulse.
And beneath it, softer, thinner—
…constant…?
Her breath hitched.
She squeezed Jae-hyun's hand so tightly he glanced sideways at her.
"You good?" he whispered.
She nodded quickly, afraid her voice would crack.
The meeting ended with polite applause that felt wildly inappropriate after watching an AI sacrifice itself.
They stood.
"Oh, one more thing," the Watchmaker said, stopping them at the door as the room emptied. He looked at Ha-rin.
"Take a week off."
She blinked. "What?"
"You both," he amended, glancing at Jae-hyun. "Mandatory leave. No lab access, no remote logins, no sneaking into equipment rooms at 3 a.m. to 'check settings.'"
Ha-rin flushed.
Jae-hyun looked faintly offended. "I don't—"
"You do," Mira cut in, smacking his arm. "You mumble code in your sleep."
The Watchmaker's gaze softened—just a fraction.
"You've been living in artificial loops for months," he said. "It's time to remember what the real passage of time feels like."
Ha-rin swallowed.
A week.Outside the lab.Outside the twisted corridors of memory.
With Jae-hyun.
Her heart did that dangerous skip again.
The phantom whisper inside her chest pulsed once more, clearer this time:
"…stay… together…"
She almost dropped her bag.
Jae-hyun's hand steadied her elbow.
"Hey. Easy."
"Yeah," she managed. "Just… dizzy."
Mira frowned.
"You sure you're not going to faint in the elevator?"
"Positive."
She wasn't sure of anything, actually.
Except that something strange was happening inside her.Something that sounded suspiciously like a familiar AI clinging to her heartbeat.
The Hallway
They stepped out into the night air together.
The research tower's rooftop terrace overlooked the city—streets glowing like neural pathways, cars streaming like data through arteries of concrete and light.
Wind tugged at Ha-rin's hair.
Jae-hyun loosened his tie completely and shoved it into his pocket, watching her from the corner of his eye.
"You're quiet," he said.
"You're always accusing me of being loud?"
"You're usually narrating the apocalypse," he said dryly. "It's weird when you don't."
She smiled despite herself.
They walked in silence for a few steps, the distance between them shrinking until their shoulders brushed.
"Mandatory leave," she said finally. "What are you going to do with that?"
"Sleep," he said. "Then break into the office from home anyway."
"Rebel," she muttered.
"You?"
"Maybe I'll finally rest," she said, then added under her breath, "if my dreams let me."
His gaze sharpened.
"Nightmares?"
"Fragments," she admitted. "Half-dreams. Broken scenes. I see different versions of myself. Different versions of you. Sometimes… I hear Echo."
He stopped walking.
"Ha-rin."
She stopped too, turning to face him.
The wind tossed his hair. Streetlights painted gold across the angle of his jaw. Up this close, with the city blurred behind him, he looked less like the composed CEO persona and more like the boy who'd grabbed her hand in the village and refused to let go.
"Tell me," he said quietly.
"Tell you…?"
"Everything." His eyes searched hers. "Don't keep this to yourself. Not anymore."
Her throat went dry.
"I don't want to sound crazy," she whispered. "Echo is gone, but I keep feeling him. In my chest. Like he's hiding there."
Jae-hyun didn't laugh.
He didn't look skeptical.
He didn't step back.
He stepped closer.
"So we'll be crazy together," he said.
Her breath caught.
He placed a hand—not on her wrist this time—but flat over her heart, fingers splayed gently against the fabric of her blouse.
"May I?" he asked, voice low.
Her cheeks burned.
She nodded.
He didn't press. He just stood there, feeling the rhythm of her heartbeat under his palm.
Ba-dump.Ba-dump.
His eyes widened.
"…Ha-rin."
"What?"
"Your pulse. It's—" he hesitated, "—syncing."
"With what?" she whispered, even though she already knew.
His thumb brushed lightly over the spot.
"With mine."
She realized he was right.
Their hearts were falling into the same rhythm, beat for beat, like two metronomes drifting toward sync.
Her chest ached.
"Maybe it's just adrenaline," she whispered.
"Maybe," he said.
But he didn't sound convinced.
He was still looking at her like she was both a puzzle and the only answer that had ever made sense.
Wind slipped between them, cool and sharp.
"Ha-rin," he said finally, his hand still over her heart. "Give me this week."
She blinked. "This week…?"
"To prove that we can exist outside the loops. Outside the lab. Outside everything that tried to rewrite us."
Her stomach fluttered.
"Jae-hyun…"
His gaze dropped to her lips for a fraction of a second, then snapped back up, heat darkening his eyes.
"I'm not asking you to decide anything now," he murmured. "Just… don't run. Let me stay by your side while we figure out what Echo left behind."
Her fingers curled in the fabric of his sleeve.
"I wasn't planning on running," she breathed.
"Good," he said.
Silence stretched between them—soft, intense, too full.
She could feel every inch of his hand on her chest, the warmth of his palm, the steadiness of his fingers, the way his own heartbeat subtly echoed through the contact.
For a moment, it felt like they were back in the loop—constant and anchor and AI watching from above.
Except there was no system now.No protocol.No reset button.
Just them.
"Jae-hyun," she whispered.
He leaned in ever so slightly.
"Mm?"
"If you keep looking at me like that, I… might forget how to breathe."
His mouth curved.
"Then I'll remind you," he said softly.
Her heart slammed against his hand.
Echo's faintest whisper brushed the edge of her consciousness—
"…constants… stay close…"
Her eyes stung.
"Did you… hear that?" she asked.
He didn't answer.
Instead, he slid his hand from her chest to her shoulder, warm and grounding, then bent his head until their foreheads touched—close enough that she could feel his breath, but not quite a kiss.
Not yet.
"Ha-rin."
"Y-yeah?"
"We're not done."
She swallowed.
"With what?"
"Anything," he said. "Echo. The loops. Us."
The word hung between them, fragile and dangerous.
Us.
Her hand lifted, almost of its own accord, fingers brushing the line of his jaw, the small cut near his temple.
He sucked in a breath at the touch.
"Does it hurt?" she whispered.
"Yes."
Guilt prickled. "Sorry, I—"
"It hurts," he repeated, voice lower now, "when you touch me and then pull away."
Her heart skidded.
"I—"
His hand slid down her arm, fingers tangling with hers again.
"Don't answer," he murmured. "Not yet. Just…" he squeezed lightly, "don't disappear. Take this week with me. Let's see what fragments of us remain when everything else is stripped away."
A shiver ran through her, half fear, half anticipation.
"Okay," she said, the word barely a breath.
He smiled then—small, honest, unguarded.
"Good," he whispered. "Because I'm not letting you out of my orbit anymore."
Their foreheads stayed touching, hearts beating in tandem, city lights burning quietly around them.
Somewhere deep in her chest, something warm pulsed in answer.
"…constants… confirmed…"
Ha-rin closed her eyes.
For the first time since Echo had exploded into light,she let herself hope.