"Some doors were never meant to be opened, yet curiosity always finds the key."
The early light slanted through Jiwoo's window, laying pale stripes across the dining table where the photograph still rested. Her father's face stared back at her, gentle and distant, beside a woman she did not recognize. The edges of the photo were slightly curled, as if time itself had tried to keep it hidden. Jiwoo flipped it over again, the handwriting sharp and deliberate.
She holds the key to everything.
Her fingers trembled as she read it for the fifth time. The words had weight—an accusation, a clue, a promise. Jiwoo's pulse quickened. She reached for her phone and called Jungwoo before her thoughts could drown her.
"Oppa," she said the moment he answered. "We need to talk."
"I was about to call you," Jungwoo replied quietly. "There's something you need to know."
"You hate me, don't you?" she asked suddenly. The question left her lips before she could stop it.
"What? No, of course not. Why would you even—"
"Because you're hiding the truth from me," she cut in, her voice sharp, trembling. "You always have."
There was a pause—long, heavy, filled with the kind of silence that means guilt.
"Come to my office," he finally said. "You deserve an explanation."
Jiwoo hung up without answering.
An hour later, she stood before his desk, the photograph clutched tightly in her hand. Without a word, she threw it onto the polished wood, the picture sliding toward him.
"Who is the woman in the photo?" Her voice cracked slightly but her eyes stayed fixed on him. "And what is Project Crimson?"
Jungwoo's jaw tightened. He removed his glasses, placed them on the desk, and let out a weary sigh. "Her name is Dr. Min Seo-yeon," he said. "She was Father's research partner. Together, they worked on Project Crimson—a serum designed to enhance cognitive abilities. Faster thought processing, perfect memory, sharper perception. It was supposed to be revolutionary."
Jiwoo stared at him, bewildered. "A serum? And someone tried to kill her… for that?"
He turned toward the tall mirror behind his desk, as though seeing another version of himself in the reflection. "Because the serum was never completed," he murmured. "appa realized what the government—or others—planned to do with it. He destroyed every trace of it… except one vial. Dr. Min vanished soon after."
Jiwoo took a step closer, anger rising with fear. "You're saying all this like it's normal. Like this is just another classified secret. Why would Appa hide this from us?"
Jungwoo turned back to her, his voice soft but steady. "Because it wasn't just his project anymore."
"What do you mean?"
He looked at her for a long moment before speaking. "The serum—legally, genetically—is registered under his name. And yours."
Her heart stilled. The words didn't make sense at first. "Mine?"
"Yes," Jungwoo said quietly. "You're part of it, Jiwoo. In ways you can't imagine."
Jiwoo's mouth went dry. The ground beneath her felt unsteady, as if the world she knew had cracked open. "You mean… I was part of an experiment?"
Jungwoo didn't answer. He didn't need to. His silence was enough.
That night, the air inside Jiwoo's apartment was thick with unease. Joonhyuk sat at his desk, scrolling through surveillance footage with a tired gaze. The blue glow of the monitors flickered across his face as he fast-forwarded through the endless feed. Then suddenly, he froze.
The frame on the screen showed a shadowed figure entering an old building. The resolution was grainy, but he knew that face. He leaned forward, whispering to himself, "Dr. Min… You're still alive."
He didn't think twice. Grabbing his coat and gun, he left the apartment.
When Jiwoo saw him heading out, she caught the keys from the counter. "You're not leaving me behind," she said, defiant.
"Jiwoo—"
"Either take me with you, or I'll follow you on my own."
Joonhyuk exhaled sharply, realizing there was no winning this. "Fine. Stay close. No heroics."
The drive was silent, the city lights fading into shadows as they reached the outskirts. The abandoned laboratory loomed like a ghost, its walls cracked, glass shattered, rust spreading like veins across the metal doors. Dust coated everything, but there were footprints on the floor—fresh ones.
"This place gives me the creeps," Jiwoo whispered.
"I told you not to come," Joonhyuk muttered.
"Can you stop being sarcastic for one second?" she shot back.
"Fine," he said with a small smirk. "Then do me a favor—don't wander off."
They stepped inside. Somewhere in the dark, something creaked. Then a voice spoke.
"I was wondering when you'd find me."
Jiwoo froze. From behind an overturned table, a woman emerged—her face pale, her hair tied back, her expression sharp and knowing.
Joonhyuk raised his gun instantly, but the woman only smiled. "No need for that, Agent Joonhyuk," she said smoothly. "I'm not your enemy. My name is Dr. Min Seo-yeon."
Jiwoo felt her breath catch. "You're… my father's partner."
"And his friend," Dr. Min said softly. "Once, at least."
She led them down a narrow hallway to a hidden room sealed behind a false wall. Inside were shelves lined with dusty notebooks, glass vials, half-built machines, and documents covered in equations Jiwoo couldn't read.
"Your father and I were close to finishing the serum," Dr. Min explained. "But when he realized the potential for misuse, he destroyed everything. Everyone believed it was lost… except one vial."
Jiwoo's hands trembled. "I… think I have it."
Dr. Min's gaze sharpened. "No. You don't. But someone close to you does."
Jiwoo stepped forward, her voice shaking. "Who?"
Dr. Min shook her head slowly. "I don't know who has it. But I know this much—whoever holds it is being watched."
Far across the city, Jungwoo stood alone in his apartment. He unlocked a hidden safe behind a painting, revealing a small glass vial glowing faintly blue under the dim light. He held it in his palm, eyes filled with conflict.
"I promised to protect her," he whispered to himself. "But at what cost?"
Back at the lab, the tension thickened. Jiwoo was still questioning Dr. Min when an alarm suddenly wailed, piercing the silence. Red emergency lights flashed across the walls.
Joonhyuk grabbed Jiwoo's wrist. "We've been compromised. Move!"
They ran through the corridor, footsteps pounding, heartbeats racing. The metal door ahead of them burst open. A masked figure stepped through, flanked by others in dark gear.
Jiwoo's breath hitched. "Who are they?"
Joonhyuk pulled her closer, his voice low but steady. "Stay behind me."
The masked figure tilted their head slightly, as if studying her. The glow from the red lights reflected off their visor—cold, unreadable.
And then, without a word, the figure raised their weapon.
The last thing Jiwoo saw was her own reflection in a cracked mirror beside the door, wide-eyed and frozen in the glare of crimson light.
Everything went dark.