The envelope lay open on the desk between them, its cream-colored flap curling gently under the draft of the overhead fan. The air in the office was no longer still—it felt disturbed, as if something unseen had been dragged into the room behind them, trailing its weight across the floor.
Se-ri stood stiffly, arms crossed tight against her ribs, staring at the piece of lined paper inside. The handwriting was crisp, deliberate, like someone had practiced each letter a dozen times before putting pen to paper.
Five words.
He lied about the fire.
She didn't touch the paper. Not yet. It felt too close, too personal, like it might burn her fingertips.
Joon-ho hovered beside her, one hand clenched slightly in the air, though it phased through the desk without landing.
"I didn't write that," he said quietly. "And I didn't see anyone put it there."
Se-ri glanced at him, brows furrowed.
"Someone got into the building."
"She must've come while we were upstairs."
"She?"
Joon-ho nodded toward the envelope. "The handwriting's neat. Balanced. Slightly right-leaning. It's a woman's hand."
"You can tell that just by looking?"
"I practiced forgery as a hobby in law school."
She stared.
He shrugged. "Just signatures. Mostly professors. It helped with grading curves."
She turned back to the envelope. "So we think it's a woman. We think she was in this building while we were upstairs. She got into your old filing cabinet—without breaking the lock—left this, and vanished."
Joon-ho nodded once.
Se-ri let out a low breath and picked up the envelope itself again. She turned it over in her hands. No watermark. No seal. Just her name. Written as if the sender knew exactly how she'd read it: slowly, warily, as if the paper might whisper back.
"Do you recognize the handwriting?" she asked.
Joon-ho hesitated. "No. But I have a theory."
"Don't say ghost."
"I wasn't going to."
She gave him a look.
"Not this time," he added, deadpan.
Se-ri carefully lifted the paper and held it up to the window. No indentations. No trace of a second sheet. The paper was clean. New.
She set it down gently and pulled her laptop closer. With a few swift keystrokes, she opened the folder labeled Witness Archive and scrolled through the scans she had just uploaded that afternoon.
"Do you think it could be one of the letter writers?" she asked.
"Possibly. Many of them never signed."
Se-ri began opening each image file one by one, comparing the loop of the 'e', the pressure on the final strokes, the angle of the slant. Some letters were rushed. Some uneven. But one caught her attention—an unsigned letter on lined paper, written in blue pen, dated April 9, 1987.
She zoomed in.
It read:
"He told me I'd be protected. But now they've stopped answering my calls."
The 't' was crossed with a sharp, high slash. The 'd' had a tiny loop at the stem. And the handwriting, though a bit shakier, had the same lean. The same round curve to the 'o'.
"This one," she said. "It's close."
Joon-ho leaned in, his form flickering slightly as he tried to focus.
"I remember this," he murmured. "She mailed it directly to the office. No return address."
"Do you remember anything else about her?"
"No name. No voice. But I think—" He paused. "She worked inside the warehouse. Payroll division."
Se-ri's eyes lit with recognition. She reached across the desk and opened the original binder from the storage room. Inside, pressed between two pages, was a smudged employee roster from 1986.
She ran her finger down the page.
There it was.
Yoo Mi-ran. Payroll Supervisor.
The only female employee listed that year.
Se-ri looked up at Joon-ho.
"She's the one who sent the letters. And now she's back."
His brow furrowed. "But why not show her face? Why not knock like Officer Oh?"
Se-ri's gaze slid toward the window.
"She's scared."
They both fell silent.
For the first time since the investigation had begun, Se-ri felt a crack in the world around her—like something fragile had been loosened from its place. Someone had stepped through the shadows of a past that was supposed to be sealed. Not to confront. Just to nudge. Just to say: I remember too.
She picked up the envelope again and turned it over once more.
Still blank.
Still warm.
Ten minutes later, Se-ri was crouched on the floor near the filing cabinet, flashlight in hand, scanning the lower drawers for any signs of forced entry.
Joon-ho stood behind her, arms crossed.
"I never thought you'd be the get-on-the-floor-and-dust-for-fingerprints type."
"I'm not," she muttered. "But I also didn't think people would start breaking into my office and leaving notes like it's a scavenger hunt."
She pulled open the bottom drawer.
Empty.
Except—
Something shifted.
A faint, paper-thin sound.
She reached deeper.
Her fingers closed around the edge of a folded piece of glossy paper wedged behind the drawer.
She tugged gently, careful not to tear it.
It was a photograph.
Color. Slightly bent at the corners. The image had faded over time, the colors sun-bleached into vintage hues.
It showed four people standing in front of the warehouse. Late afternoon sun. Two men in suits, one with glasses. A younger man with an employee badge around his neck. And a woman in a gray skirt and blazer, her hair tied back, her expression cautious but composed.
Se-ri recognized the woman instantly.
The same lean in her shoulders. The same posture.
Yoo Mi-ran.
She held the photograph up.
"Here," she said.
Joon-ho moved closer, his eyes narrowing.
"That's her," he said. "And that—" he pointed to the man with glasses "—that's Seok-dae. The one who testified against Choi."
"And this?" She pointed to the tall man in the back, face half-shadowed.
Joon-ho stiffened.
"I don't know."
Se-ri looked at him. "You've never seen him before?"
"No. But I don't like the way he's standing."
She studied the photo again.
The man's hand was resting on Yoo Mi-ran's shoulder. Lightly. Possessively.
She placed the photo beside the envelope on the desk, arranging them like puzzle pieces.
"What if she's trying to tell us something?" she said. "That she saw something. That she still knows something."
"Then we need to find her," Joon-ho replied.
Se-ri opened her laptop again, fingers moving quickly across the keys.
She typed Yoo Mi-ran Seoul payroll 1987, then warehouse arson case, then narrowed the search to obituaries, employment records, anything.
Nothing came up.
Not even a footnote.
It was like she'd disappeared.
Se-ri sat back, frustrated.
"Nothing," she said. "Not a trace."
"Try municipal registries," Joon-ho suggested. "Old address forms. Voter rolls."
She nodded and pulled out her phone, preparing to contact the local district office for archived records.
Before she could dial, a faint sound cut through the room.
A scraping noise.
Slow.
Deliberate.
Both she and Joon-ho turned toward the source.
The stairwell door at the back of the office—the one leading up to the third floor—was ajar.
They had closed it earlier.
Se-ri stood slowly.
"Did you open that?" she asked.
Joon-ho shook his head, voice low. "No."
She approached it, her feet silent on the floorboards.
The hallway beyond was empty. Quiet. But the door was moving—just slightly. Like it had been nudged. Or pushed.
She stepped into the stairwell, her eyes adjusting to the dim light.
Nothing.
But—
There. On the top step.
A single, new object.
She climbed slowly, her fingers brushing the rail.
And stopped when she reached it.
It was a red business card.
Glossy. Pristine.
No name on the front.
Just a single embossed symbol: a flame.
She turned it over.
Words were written there, scrawled in sharp, angled script.
"Some fires never die."