Morning arrived quietly.
The detention center never really slept.
Doors opened.
Keys turned.
Voices echoed through concrete corridors with the same rhythm they had yesterday.
Routine.
Predictable.
Everything except the people inside.
Seo Hae-in walked through the security gate without breaking stride.
Today's outfit was different.
Still black.
Always black.
But instead of the severe courtroom tailoring she usually wore, she chose a long structured coat that reached just below her knees over a fitted turtleneck and sharply tailored trousers.
No jewelry.
No unnecessary detail.
Only clean lines.
The officers barely looked at her.
They recognized her now.
That wasn't an advantage.
It meant people were watching.
The father sat alone in the interview room.
His hands rested on the table.
Not clenched anymore.
Just...
still.
He looked up when she entered.
"I was beginning to think you weren't coming."
"I said I'd be back."
"You did."
A faint smile appeared.
Small enough that someone else might have missed it.
She didn't.
She sat down across from him.
No files.
No photographs.
No evidence.
That surprised him.
"No questions today?"
"I have one."
He waited.
"What did your daughter laugh like?"
He stared at her.
For several seconds he didn't answer.
Not because he didn't want to.
Because he wasn't expecting the question.
"...Why?"
"Because everyone keeps asking about the night she died."
She leaned back slightly.
"I'm asking about the years before it."
Silence settled between them.
Then—
he laughed.
Just once.
Quietly.
"She snorted."
Seo Hae-in blinked.
He looked embarrassed.
"Whenever she laughed too hard..."
His eyes drifted somewhere beyond the room.
"...she'd try to stop herself."
He demonstrated by pressing his lips together.
"It never worked."
Another small laugh escaped him.
"There was always one little snort."
The room felt different now.
Lighter.
For only a moment.
"She hated that."
"I told her it made her laugh sound real."
His smile faded slowly.
"I don't remember the last thing I said to her."
Silence.
"I remember teaching her to ride a bicycle."
A pause.
"I remember helping with homework."
Another pause.
"I remember buying her a birthday cake she said was ugly."
His voice cracked slightly.
"But..."
His fingers curled against the table.
"I can't remember the last time I told her I loved her."
Seo Hae-in didn't interrupt.
Some silences deserved to exist.
Outside the room, the detective watched through the observation window.
"That's not an interrogation."
Another officer shook his head.
"No."
"What is she doing?"
The detective answered quietly.
"Finding the man."
Inside, Seo Hae-in finally spoke.
"Tell me about the bicycle."
He looked confused.
"The bicycle?"
"You remembered it first."
He thought for a moment.
"It was blue."
A small smile returned.
"Far too big for her."
"She insisted she could ride it."
"She couldn't."
He chuckled again.
"I spent three hours running behind her."
"And?"
"I let go."
His expression changed.
"I didn't tell her."
"You wanted to see if she'd notice."
He nodded.
"She rode almost half the street before realizing I wasn't holding the seat anymore."
His eyes became distant again.
"When she looked back..."
Another pause.
"...she was smiling."
His voice lowered.
"I've been trying to remember that smile every night."
He looked at Seo Hae-in.
"I'm scared one day I'll forget that too."
For the first time—
her expression softened.
Barely.
"You won't."
He searched her face.
"You sound very certain."
"I'm choosing to be."
Back at her office—
the investigation board covered almost the entire wall now.
Photographs.
Timelines.
Names.
Audio reports.
Security records.
But beside the victim's photograph...
she pinned something new.
A child's drawing.
Recovered from the apartment.
Simple.
Crayon.
A crooked house.
A stick figure holding another stick figure's hand.
The detective looked confused.
"Why put that there?"
Seo Hae-in studied the drawing.
"Because every piece of evidence tells us how she died."
She looked back at the picture.
"This reminds me how she lived."
He didn't answer.
Her phone rang.
The forensic lab.
"We finished examining the drawing."
She frowned slightly.
"You examined it?"
"You asked us to test everything from the apartment."
She had.
Even the things everyone else ignored.
"There are fingerprints."
"Expected."
"Not those."
A pause.
"Someone else's."
Seo Hae-in straightened.
"An adult?"
"Yes."
"The father's?"
"No."
Silence.
The technician continued.
"They don't match anyone currently connected to the investigation."
She didn't speak.
The drawing suddenly became more than a memory.
It became evidence.
Small.
Incomplete.
But real.
"Send me everything."
That evening—
the father sat alone in his cell.
He closed his eyes.
Trying again.
Searching.
Not for the night.
For her voice.
Nothing came.
He lowered his head.
Then—
without understanding why—
he began humming.
Softly.
A melody.
Only four notes.
The guard passing outside stopped walking.
He listened for a second.
Then continued down the corridor.
The father didn't even realize he was humming.
But somewhere else—
someone listening through an intercepted security recording paused the playback.
The melody.
They recognized it.
And for the first time—
they understood something had survived.
Not a memory.
A habit.
Sometimes...
the deepest truths weren't stored in the mind.
They were stored somewhere even harder to erase.
End of Chapter 15