The library doors closed behind Soo-jin.
Hae-in remained at the table.
The black notebook sat between her hands.
She didn't open it again immediately.
She was thinking about the sentence on the final page.
If Hae-in finds this, tell her the truth about her father.
Not tell Hae-in what happened.
Not tell her what her father did.
Tell her the truth.
There was a difference.
Kang returned a minute later.
"Lost him."
Hae-in looked up.
"Soo-jin too."
He stared at the empty chair.
"She left?"
"Without us noticing."
Kang sighed.
"She's good."
"She has practice."
He sat down.
"What did you find?"
Hae-in pushed the notebook toward him.
"Seven names."
He opened it.
The first six had been crossed out.
The seventh had not.
Kang read the names carefully.
Then stopped.
"I know this one."
Hae-in watched him.
"Who is he?"
"Park Min-jae."
"Why do you know him?"
Kang turned another page.
"He was listed as a witness in the original investigation."
Hae-in's expression hardened.
"Original investigation?"
"The case before you took over."
"When?"
"Eight years ago."
Silence.
Hae-in looked back at the photograph.
Her father.
Soo-jin.
The detention center.
The seven missing people.
Everything was beginning to overlap.
Kang continued.
"Park Min-jae was reported dead in 2019."
"Cause?"
"Traffic accident."
"Where?"
"Outside Seoul."
Hae-in reached for the notebook.
"Was the body identified?"
Kang hesitated.
"That's the strange part."
She looked at him.
"Go on."
"The identification was based on dental records."
"No family confirmation?"
"No."
"DNA?"
"Not in the original file."
Hae-in slowly closed the notebook.
"Then we don't know if the person who died was Park Min-jae."
Kang nodded.
"We don't."
The original case file was stored at the central police archive.
They arrived just before closing.
Kang signed for the file while Hae-in waited.
The archivist returned with a thin brown folder.
"That's all?"
Kang looked surprised.
"This was a major investigation."
"That's everything that remains."
Hae-in took the folder.
She opened it on the counter.
Traffic accident photographs.
Medical report.
Identification form.
Death certificate.
Nothing unusual.
Until she reached the final page.
A handwritten note.
The ink was faded.
Identification disputed by witness.
Hae-in frowned.
"Who disputed it?"
The archivist looked over.
"I don't remember."
Kang checked the file.
"There's no name."
Hae-in turned the page over.
Nothing.
She looked at the death certificate again.
Then at the date.
"Why was the case closed so quickly?"
Kang checked the report.
"Three days."
"Three days?"
"Accidental death. No evidence of foul play."
Hae-in stared at the photograph attached to the report.
The face was badly damaged.
Enough to make identification difficult.
But there was something else.
A small scar beneath the left ear.
She remembered Soo-jin's photograph.
Park Min-jae had the same scar.
Or—
someone had wanted them to think he did.
Hae-in closed the file.
"Get me the dental records."
Kang looked at her.
"Now?"
"Now."
Two hours later, the comparison arrived.
Hae-in stood beside the printer as Kang read the report.
His expression changed.
"What?"
He looked at her.
"They don't match."
She said nothing.
"The dental records from the body belong to someone else."
Hae-in's eyes narrowed.
"Who?"
Kang checked the identification number.
"Unknown male."
The room went quiet.
"So Park Min-jae never died."
"No."
"Someone gave them another body."
"Yes."
Hae-in looked at the notebook.
Seven names.
Six crossed out.
One still alive.
She understood.
The crossed-out names weren't necessarily dead.
They were removed.
Park Min-jae was the only one whose disappearance had left enough evidence to expose the pattern.
Someone had erased six people.
And now someone was trying to erase the seventh.
Her phone rang.
Unknown number.
She answered.
No greeting.
A man's voice came through.
"You shouldn't have opened that file."
Hae-in's expression remained calm.
"Then you shouldn't have left it."
Silence.
The man laughed softly.
"You sound like your father."
Her fingers tightened around the phone.
"What did you know about him?"
Another pause.
Then:
"He knew what happened to the seven."
"Who were they?"
"You already have their names."
"Where are they?"
The voice became quieter.
"One is dead."
Hae-in waited.
"One is missing."
Another pause.
"And the others?"
"You'll find out."
The call ended.
Hae-in lowered the phone.
Kang looked at her.
"What did he say?"
She looked at the seven names.
Then at the final one.
"He's afraid we're getting close."
Kang nodded.
"That's good."
"No."
Hae-in picked up her coat.
"It's not."
She looked toward the archive door.
"If they're afraid, they'll move."
"And?"
"We need to find Park Min-jae before they do."
Outside, the city had become dark.
Kang started the car.
Hae-in sat in the passenger seat, the notebook resting on her lap.
She opened it one more time.
The seven names stared back at her.
At the bottom of the page, beneath Park Min-jae's name, there was something she hadn't noticed before.
A tiny number.
17.
She turned the page.
Nothing.
She checked the previous page.
Nothing.
She checked the photograph.
Nothing.
Kang glanced at her.
"What is it?"
"I don't know."
She held up the notebook.
"There's a number."
"Seventeen?"
"Yes."
"Could be a page reference."
"There is no page seventeen."
Kang looked at the notebook.
Then at her.
"Maybe it's a room."
Hae-in froze.
A room.
The detention center.
Cell Block C.
Maintenance records.
Seventeen.
She immediately reached for her phone.
"Call the detention center."
Kang did.
After a moment, his expression changed.
"What?"
He covered the phone.
"Cell Block C has seventeen cells."
Hae-in looked out through the windshield.
"Then we know where to start."
Kang returned to the call.
The car pulled away from the curb.
Neither of them noticed the black sedan parked across the street.
Inside it, someone watched them leave.
On the passenger seat was a photograph.
Seven people.
Six faces had been crossed out.
One remained.
Park Min-jae.
A hand slowly placed a red line beneath his name.
Then another photograph was placed beside it.
A photograph of Seo Hae-in.
The voice from the phone call came through the car's speakers.
"She found the seventh."
A second voice answered.
"Then it's time to move the eighth."
The line went silent.
And somewhere beneath the city—
a locked door marked 17 opened.