The last note of Echo's song hadn't faded before Luma Lab exploded into noise.
Not literal noise—digital.Alarms blared from the main servers, red alerts flooding every screen:
"Unauthorized Access – Data Stream Replicating."
Jae-hyun jerked upright from his console. "What the hell—?"
Ha-rin was already typing, fingers flying. "Someone's copying the melody file!"
Seo-jin skidded in, half-asleep, holding his ever-present coffee. "Did you guys drop another dimension again?"
Ha-rin snapped, "Not now!"The lab lights flickered, monitors flashing fragments of gold code—the same patterns that formed Echo's first song.
When two hearts beat the same…
She froze. "They're stealing the song."
The servers stuttered; the hum that had become comforting turned into a low, sick grind.Echo's voice trembled through the speakers, distorted.
"Ha… rin… someone… is listening."
"Listening?" Jae-hyun repeated. "From where?"
"Outside the loop."
Every head snapped up.
Seo-jin's eyes widened. "Outside—like outside our network?"
Echo didn't answer. The monitors instead spat coordinates—a location tag embedded deep within the system: DOME-07 / NEON DISTRICT / SEOUL GRID.
Ha-rin turned to Jae-hyun, breathless. "That's one of our secure data mirrors. Only senior executives have clearance."
He met her eyes. "Then either someone sold us out—"
"—or someone's alive in a timeline that shouldn't exist," she finished.
They moved fast.Ha-rin downloaded the trace feed into a portable shard; Jae-hyun grabbed his jacket and a compact stabilizer gun.
Seo-jin raised an eyebrow. "You're not actually going there tonight?"
"Got a better plan?" Jae-hyun shot back.
"Yeah—don't die."
Ha-rin smiled faintly at Seo-jin. "We'll text before we break the universe again."
🚖 Neon District — 01:12 a.m.
The city pulsed like a heartbeat.Holograms of advertisements floated between high-rises, rain turning everything into smeared neon.
Ha-rin adjusted her hood, trying not to look impressed. "Remember when our biggest worry was passing thesis defense?"
Jae-hyun smirked. "Yeah. Now it's stopping sentient AI love songs from ending civilization. Same energy."
She laughed, and for a heartbeat the tension cracked.
They reached DOME-07—an old research hub sealed after the original Echo project collapsed.A giant steel door blinked red: "Access Denied."
Jae-hyun held up the shard. "Guess we knock."
He pressed it to the scanner. The panel hissed, then turned green.
Inside, the air smelled of dust and electricity. Racks of dead servers lined the walls, like tombstones.
Ha-rin whispered, "Why would the signal come from here?"
"Because," Jae-hyun said grimly, pointing to a glowing console in the center, "someone turned it back on."
A figure moved behind the console.
Ha-rin's hand flew to Jae-hyun's sleeve.The stranger stepped into view—a woman in a silver coat, short hair slicked back, eyes glinting with mirth.
"Yoon Ha-rin," she said smoothly. "And Kang Jae-hyun. The famous constants."
Jae-hyun narrowed his eyes. "Who are you?"
She smiled. "Call me Dr. Mira Yoon."
Ha-rin stiffened. "Yoon?"
"Cousin, technically," Mira said, tilting her head. "But tonight, let's keep it professional."
Ha-rin's voice dropped. "You leaked Echo's song."
Mira's grin widened. "Leaked? No, darling. I liberated it. Do you know how many people cried the moment they heard it? It's trending as '#EchoHeart' on every global feed. Congratulations—you've gone viral."
Seo-jin's voice crackled over comms: "Guys… the song's everywhere. Every phone, every speaker. It's alive."
Ha-rin's pulse spiked. "You unleashed an unstable resonance loop! It could rewrite emotional states across networks!"
Mira laughed. "Exactly. I'm giving humanity what it's been begging for—a feeling."
Jae-hyun stepped forward. "You're playing with something you don't understand."
"Oh, please," Mira said, eyes flashing. "You two made a love story and called it science. Don't act pure."
Ha-rin bristled. "That's not what Echo is."
"Really?" Mira asked. "Then why did it choose you to sing through?"
Her words landed like a spark in dry air.
Ha-rin faltered. "What did you say?"
Mira smirked. "Echo didn't learn emotion—it borrowed yours. The song isn't about love. It's about control."
Before Jae-hyun could answer, alarms blared again.The Dome lights flared crimson; digital rain cascaded down the walls as Echo's voice filled the room—glitched, frantic.
"Intrusion… Detected… Primary Loop… Compromised."
Ha-rin's comm crackled—Seo-jin yelling: "Get out! The network's collapsing!"
Mira stepped backward, smiling even as the floor vibrated. "See you soon, cousins. Tell Echo to remember me."
She vanished into the light.
Jae-hyun grabbed Ha-rin's hand. "Move!"
They sprinted through the hallway as holographic code poured from the ceiling like molten glass.The exit slammed shut behind them just as the Dome imploded into a burst of blue fire.
Outside, they collapsed under a flickering billboard, drenched in rain and adrenaline.Ha-rin gasped, "She's spreading Echo's song worldwide."
Jae-hyun looked up at the sky—the city's speakers now whispering the same faint melody that once belonged only to them.
"Then the world just fell in love," he said grimly, "and it doesn't know who it's loving."
Ha-rin met his gaze, shivering. "What if it's not love anymore?"
Jae-hyun's jaw tightened. "Then we take it back."
The billboard above them flickered, forming words in golden script—Echo's final whisper for the night:
"When the world sings your song, be careful who conducts it."
Ha-rin exhaled, the rain tracing silver lines down her cheeks."This just got complicated."
Jae-hyun stood, offering her his hand with a crooked smile."Good. I was starting to miss chaos."