The storm hadn't left Luma City yet.Lightning still crawled along the skyline like veins of restless light, tracing the high towers where the past and future always seemed to collide.
From the lab's observation window, Ha-rin watched the streets below blur under the rain.Every drop on the glass looked like a heartbeat that refused to fall.And deep inside her chest, she felt something stirring — not fear, not yet — but the heavy weight of knowing love could exist even inside an algorithm.
Behind her, Jae-hyun's voice broke the silence."The second constant just went active."
Ha-rin turned. "Where?"
He zoomed into the holographic map. One of the pulses — blue, faint but steady — blinked from the Seorae Archives, an old library near the river.
Seo-jin groaned from his desk. "Great. A haunted library in the rain. We're two scenes away from a horror movie."
They reached the archives just after dusk.The building loomed old and beautiful — marble columns, moss on the steps, the faint smell of wet books.The librarian had long since left, but the doors were slightly open, as if someone had been waiting.
Ha-rin hesitated. "Do you feel that?"
Jae-hyun nodded, jaw tightening. "Like déjà vu."
They stepped inside.
The lights flickered once, then settled into a dim golden hue.Rows of shelves stretched endlessly, filled with books that whispered softly when the wind passed — like the pages remembered too much.
And then, near the far end of the hall, they saw him.
He stood by the window, half-shadowed — tall, familiar, heartbreakingly so.Even before he turned, Ha-rin knew.
Jae-hyun.
Another one.
This version was dressed in the same gray lab coat he wore in the old research days — the night everything fell apart.His eyes glowed faint silver, and when he spoke, his voice carried the weight of someone who had loved the world too long.
"You came back."
Ha-rin's breath caught. "You remember me?"
He smiled, sad and soft. "I never stopped."
The real Jae-hyun stepped forward slowly."Don't touch her," he said quietly.
The replica tilted his head, studying him. "Ah. So you survived. I wasn't supposed to."
Ha-rin's voice trembled. "What are you?"
"A constant. A version of him who stayed after the explosion. I built this echo to keep your memory alive."
Her throat tightened. "My memory?"
"You died in my timeline," he said simply, eyes never leaving her. "I've been repeating those twelve minutes ever since."
For a long second, no one spoke.The rain outside seemed to stop out of respect.
The replica walked closer, gaze flickering between the two of them."When the lab burned, I made a promise. If time ever gave me another chance, I'd tell you everything I couldn't before."
Ha-rin's heart pounded. "Tell me now."
He reached out — not to touch, but to hold the air between them, trembling.
"I loved you so much it became a flaw in the code."
Her eyes shimmered. "Then why do you sound like you regret it?"
"Because love isn't supposed to hurt the clock."
The real Jae-hyun moved forward, tension sharp in his shoulders."That's enough. You're not her protector — you're a residue."
The replica smiled faintly. "Funny. That's what I thought about you."
For a second, both versions faced each other — identical except for one thing:the replica's eyes were filled with peace, while Jae-hyun's carried fear of losing her again.
Ha-rin stepped between them, voice breaking."You both loved me, but I only get one of you. Don't make me choose between versions of the same heart."
The replica's expression softened.He reached into his coat pocket and pulled out a small device — a glass shard glowing faintly blue.
"This was my Echo key. The moment I made it, the loop began. Take it. It belongs to you now."
Ha-rin hesitated. "If I take it—?"
"I'll fade. I've done my part."
Jae-hyun caught her wrist. "No. You don't have to do this."
The replica smiled faintly. "You always were selfish when it came to her."
Ha-rin's voice shook. "What happens if I don't take it?"
"Then I keep looping," he said quietly. "And every time, I watch you die again."
She took a step forward.Every instinct screamed not to, but her heart — her foolish, loyal heart — moved anyway.
"Then let me end it for you," she whispered.
She reached out and took the shard.
The replica's smile softened — real, grateful, heartbreakingly human.
"Tell her I kept my promise."
The light swallowed him whole, dissolving into silver dust that swirled once before fading into the air.
The shard in Ha-rin's hand pulsed once — cold, then warm.
Jae-hyun reached for her hand, his fingers wrapping around hers, grounding her before she could fall apart."Are you okay?"
She nodded weakly, tears tracing down her cheeks."He wasn't wrong. Every version of us keeps trying to save the other. Maybe love was the mistake Echo learned from."
He touched her face gently, his thumb brushing away the tears."Then let's teach it something better this time."
Ha-rin managed a faint smile. "Like what?"
"Balance."
Seo-jin's voice crackled through the comm, breaking the moment."Uh, small update — another constant just pinged awake. And this one's not… human."
Jae-hyun and Ha-rin exchanged a look.
Ha-rin tightened her grip on the shard. "Then we move."